camshaft for torque

ok my last post was a little general to say the least,so ill start on the basics

(this is for a 350 chevy sb by the way)

being a series III landy my 'racer' is quite heavy. obviously being a heavy off-roader while being used for daily driving it needs a short duration cam with buckets of torque. BUT ill be doing rallies etc. so ill be reving it at times too, so just a little top end power would be good (max 5500 rpm)

having looked around/read the tech, i was thinking of....
around 112 lobe separation
215 degress duration at 0.050
270 duration
0.500 lift

any particular makes to go for? Crane or Comp Cam prehaps.
will i loose a lot of top end power if reduce the duration by 5 or 10 degrees for more torque and mid power? is this combo ok as a start point?
cheers guys

What motors do they put in those rovers? Cubic inch and bore and stroke? Longer stroke will allow you to get away with a little more duration while still maintaining good low end torque.
I'm not at all familiar with a Rover engine though.

Well with my limited experience with the SBC I have refered Lobster to several SBC sites so other folks should know that maybe Lobster is thinking of putting a SBC in his Rover, is that so? Otherwise what is said above is also true that increasing the stroke in whatever engine does help low end torque. Lobster, the thing to do is specifically tell us what engine you are looking at and somehow get Tech1 to reply or even send him an e-mail. He forgot more than most of us know about cams, although some other folks on this Forum also know about how to wring torque/HP out of a V8 whether Ford, SBC or Mopar. Try to tease Tech1 into an answer and consider carefully what he says but you need to spec your engine more completely.

Don Shillady
Retired Scientist/teen rodder

My Comp XE256H cam did a 2.3 second 60' in the quarter mile in my 76 GMC half ton equiped with a stock 1200 rpm torque converter and 3.07 gears. Tires were BFGoodrich Long Trail 265/70r15, nothing super sticky. It ran 15.3 overall in the quarter mile at 88 mph. Bascially, it makes a lot of torque to get the lump rolling with only 3.07 gears. I'm guessing around 420 ft lbs at the crank. The cam really runs out by 5500, though. An XE262H will make power well through 5500 rpm. I'm also running just a performer intake, if you ran a performer rpm intake with the XE256, it would probably wake up the top end a little.

Bugger! Forgot the minor detail....... yes im talking about a chevy 350. Ive had enough of crap rover engines.

im not too keen about increasing the stroke as i want to keep engine size down for ecconomy and engine classes for competitions. maybe in the future eh?

the Comp XE265H sounds good, as i probably wont be going over 5500 revs. 420ft lbs would be great though.

would it be better to go for the XE256 with the performer RPM, or the XE262 with the performer if i wanted to gain a tiny bit of top end with minimal loss of torque?

If you went with the XE256H cam, you could go with either manifold. If you went with the XE262H, I would most certainly go with the RPM manifold. The motor I put this cam in is a 9.25:1 compression 350 with Vortec heads. If you're feeling rich, you could just buy both manifolds and try them both out. Also, match it up to a set of small diameter long tube headers. 1 5/8ths in primaries and a 2 1/2 inch collecter.

i have a 292H Comp cam in my s10, nice cam, lots of lift, lumpy, ROUGH idling, no complaints, RPM Range is 2500-6500.

Quote:

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Originally posted by Ross
i have a 292H Comp cam in my s10, nice cam, lots of lift, lumpy, ROUGH idling, no complaints, RPM Range is 2500-6500.

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I THINK HE IS LOOKING FOR A CAM WITH LOW END TORQUE NOT SOMETHING HE HAS TO RUN A 3,000 STALL WITH.

HEY LOOK I CAN RIGHT IN CAPITALS TO!

look at a 292's specs. the duration is 292 but the lift is exactly what he is looking for. hydraulic street cams dont come in that lift and duration combo. He may want a 4X4 Comp Cam though.

lift is .480, duration is 270 1300-5600 rpm range.

Xtreme 4x4 X4262H Hydraulic Flat COMP CAMS

Quote:

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Originally posted by Ross
HEY LOOK I CAN RIGHT IN CAPITALS TO!

look at a 292's specs. the duration is 292 but the lift is exactly what he is looking for. hydraulic street cams dont come in that lift and duration combo. He may want a 4X4 Comp Cam though.

lift is .480, duration is 270 1300-5600 rpm range.

Xtreme 4x4 X4262H Hydraulic Flat COMP CAMS

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UMMM,YOU MIGHT WANT TO TAKE A LOOK AT THE HYD. ROLLER CAMS COMP. CAMS SELLS.WELL WOULD YOU LOOK AT THAT .500 LIFT ON BOTH THE INTAKE AND EXHAUST SIDES AND 215* AT .050 VALVE LIFT.I THINK THOSE WHERE THE SPECS. HE WANTED.PART #08-420-8. OH,BY THE WAY DO YOU HAVE PRINCE ALBERT IN A CAN? ANYONE, ANYONE, L.O.L.

lobster, the key to doing what you say you want to do is a looser converter. Any cam you screw into a naturally aspirated motor will have an effective "window of operation" of about 3,500 rpm's, so nobody can grind you a cam that will operate effectively off-idle to over 5,000 rpm's with a stock converter.

Here's an example of a cam that will give you low-end grunt from 1,000 rpm's with a stock converter, but runs out of breath at 4,600 rpm's..... It is ground on a 110 centerline.....
http://www.cranecams.com/?show=brows...tType=camshaft

Here's the next cam on the list, making power from 1,400 to 5,000 rpm's. Personally, I'd be using a looser converter in the 1,600 to 1,800 stall range with this cam if I were doing it....Also ground on a 110 centerline.....
http://www.cranecams.com/?show=brows...tType=camshaft

This cam may be getting closer to what you're looking for, making power from 1,600 to 5,400 rpm's, but again, personally I'd install a converter with a stall of 1,800 - 2,000 rpm's.....again, 110 centerline.....
http://www.cranecams.com/?show=brows...tType=camshaft

Let me say this about specing a cam. Crane probably has the most realistic power range listings of any grinder I've used. Some of the other grinders will lead you to believe that their cams have an effective window of operation of well over 4,000 rpm's, but it just ain't so, not naturally aspirated it ain't.

Pay close attention to the required static compression ratio to be run with any cam you put in the motor and try to build the motor to the middle of the c.r. spec with zero deck and a 0.039" compressed gasket for a tight squish. That will allow you to run normal spark lead on crap pump gas.

As far as manifolds, I'd use a standard Performer with any of the 3 cams I've listed to keep velocity up for good cylinder filling. Read these recommendations from Edelbrock and make your own decision, paying attention to the operating range of each.....


Performer® Manifolds (idle to 5500 rpm)
Performer manifolds are dual-plane, low-rise intake manifolds with a 180° firing order and patented runner design that you won't find in other brands. This patented design greatly improves torque over a wide rpm range for excellent throttle response, especially off-idle through the mid-range. Throttle Performers are ideal for passenger cars, trucks, 4x4s, tow vehicles and RVs. There are EGR and non-EGR versions available for most domestic V8 and some V6 engines. Most Performer intakes are 50-state street legal, when used with the correct carburetor and in the correct application.

Performer RPM™ Manifolds (1500 to 6500 rpm)
Performer RPMs are dual-plane, high-rise intakes with 180° firing order to produce incredible top-end horsepower while retaining good throttle response. Their larger plenums and runners match the free-flowing exhaust, high-lift cams and other modifications of a high output engine. They are intended for high-performance street or competition engines that run up to 6500 rpm. They are not for emissions equipped engines. Edelbrock's Performer RPM gives you the ultimate in street high-performance.

One last thought, keeping in mind that power is in the heads, pay attention to the post by 76GMC1500 about the Vortec heads. They will outflow any of the Gen I Chevy heads ever produced and will make excellent full-time-street / part-time-track heads.

Cheers Guys!

looks like the 272 H10 (the last crane cam from techinspector1 - cheers) is what im looking for. just seems to have a much better top end with only a little sacrifice in idle etc. duration looks fine. prehaps 1.6:1 rocker ratio on the exhaust valve to improve lift?

As for the manifolds, looks the Perfoprmer kicks the RPM's ass for torque, so ill prob go for that. has anybody tried the performer air-gap or the performer EPS???? is the air gap woth the extra 100 bucks?

vortec heads would be nice but probably a bit pricey (plus having to buy special manifolds etc). IF i had a bit extra to spend, what would people recomend to buy...

full roller valve train (so higher lift cam can be used)
OR vortec heads with a standard valve train??

maybe just sell my kidneys and buy a supercharger..... mmmmmm

Personally, I'd spend money on good heads before ANYTHING else. They will be the foundation for whatever else you want to do to the motor.

Let me give you a combination to think about. You can embrace it, modify it or discard it completely, but this might be how I'd do it...

350 block bored 0.030"
Scoggin-Dickey #KB193-030 Keith Black hypereutectic pistons (12 cc dish) $31.25 each for use with 3.480" crank and 5.700" rods.

I like these pistons particularly because of the way the dish is offset to one side of the crown, allowing a generous squish pad to mate up with the squish pad on the Vortec heads.
http://kb-silvolite.com/performance....tails&P_id=155

GM 12495499 head bolt kit $24.95
GM 10105117 Vortec head gaskets (0.028" compressed) $15.45 each
GM 12495490 rail rocker arms (kit of 16) $49.95

These rockers have rails on each side to form a "trench" for the valve tip to ride in so that the rocker will stay centered on the tip without the additional expense of machining the heads for use with guide plates.

Fel-Pro FEL1255 intake gaskets (pair) $23.95
Edelbrock #E2116 Performer intake manifold $158.95
Scoggin-Dickey #SD12550027 12 point intake bolts (kit) $14.95
GM 10046089 valve cover gaskets $9.95 each
GM 12558060 Vortec heads assembled with 1.940" intake / 1.500" exhaust valves, single springs for max 0.450" lift, retainers and keepers $249.75 each

Scoggin-Dickey #BG4282010VE Barry Grant Road Demon 625 cfm vacuum secondary carb $339.95 or my personal favorite, the Rochester Quadrajet Scoggin-Dickey #E1901 Edelbrock 750. $449.95. Don't let the 750 throw you, it's not too much carb due to the tiny little primaries for excellent mileage and throttle response and the huge secondaries for power when needed.

Crane 100052 hydraulic camshaft (not listed in Scoggin-Dickey catalog, but could probably be sourced from them on special order. I'm just trying to source all parts from one supplier) Vortec heads are limited to 0.450" lift with supplied springs and this cam has 0.454" lift, talk with the tech guys at Scoggin-Dickey to find if this cam should be ground with a little less lift to work with stock Vortec springs, retainer/seal clearance.)

By the way, you mentioned 1.6 rockers on the exhaust. You won't need them with the Vortec heads. 1.6 rockers are used to crutch-up poor-flowing exhaust ports in relation to intake ports and the Vortec heads are well-balanced as cast. You'll see that some cams for the SBC are ground on a dual pattern, more lift and more duration on the exhaust side and again, this is to crutch-up the poor-flowing (relative to the intakes) stock Chevy exhaust ports. You also won't need any more lift than 0.450"/0.454" with these heads in a street application with mild track time. They flow so well that you don't need an excessive amount of cam lift to crutch them up like you might need with stock OEM Chevy castings.

Scoggin-Dickey #CRA99377-16 Crane High-Intensity lifters. $119.95 set of 16. These are fast-bleed lifters that produce a variable duration effect. At lower rpm's, these can reduce running duration by 6 to 10 degrees and decrease valve lift by 0.020" to 0.030". This controlled oil pressure increases cylinder pressure and performance in the lower rpm range without sacrificing duration and lift in the upper ranges. Somewhat like having your cake and eating it too. You may be able to run a stock converter with this cam if using these lifters. Talk to the tech guys at Crane.

Assemble the motor with the pistons 0.012" down in the bore at TDC. This will give you a squish of 0.040" using the 0.028" compressed head gaskets and will allow you to run pump gas without detonation at the calculated 9.65:1 compression ratio with the 64 cc Vortec heads and 12 cc KB pistons.

Set initial timing at the crank at 12 degrees and re-curve your distributor for total initial and centrifugal timing of 36 degrees, all in by 2,800-3,000 rpm's. Adjust fuel pressure for 5 1/2 to 6 lbs at the carb inlet. Degree the cam according to the instructions from Crane. Include a way to advance or retard it by 4 degrees after you have the motor running (offset dowel or whatever). That way, you can tailor the cylinder pressure higher or lower according to what you think you need.

Valve covers for Vortec heads...
12355350 GM Chrome With Red Bow Tie In Center
SCTZVC New “Take Off” ZZ-4 Black Valve Covers (When Available)
24502540 Valve Cover Adapter, Converts Center Bolt To Outside Bolt
10046089 Center Bolt Valve Cover Gaskets (price is for one gasket)
241-75 Holley Custom, Cast Aluminum, Ball-Milled Top, Valve Covers. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise. (Pic)
241-74 Holley Custom, Cast Aluminum, Polished Flat Top, Valve Covers. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise. (Pic)
9415 MR Gasket, 87 & up SBC , center hold down, baffled. (2 covers, 1 oil fill cap, 2 PCV/breather grommets.) (pic)


Scoggin-Dickey Chevrolet website/catalog....
www.SDPC2000.com

O.K., the old tech guy is tired from all this and is going into the other room for a nap :)

Quote:

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Originally posted by techinspector1
Personally, I'd spend money on good heads before ANYTHING else. They will be the foundation for whatever else you want to do to the motor.

Let me give you a combination to think about. You can embrace it, modify it or discard it completely, but this might be how I'd do it...

350 block bored 0.030"
Scoggin-Dickey #KB193-030 Keith Black hypereutectic pistons (12 cc dish) $31.25 each for use with 3.480" crank and 5.700" rods.

I like these pistons particularly because of the way the dish is offset to one side of the crown, allowing a generous squish pad to mate up with the squish pad on the Vortec heads.
http://kb-silvolite.com/performance....tails&P_id=155

GM 12495499 head bolt kit $24.95
GM 10105117 Vortec head gaskets (0.028" compressed) $15.45 each
GM 12495490 rail rocker arms (kit of 16) $49.95

These rockers have rails on each side to form a "trench" for the valve tip to ride in so that the rocker will stay centered on the tip without the additional expense of machining the heads for use with guide plates.

Fel-Pro FEL1255 intake gaskets (pair) $23.95
Edelbrock #E2116 Performer intake manifold $158.95
Scoggin-Dickey #SD12550027 12 point intake bolts (kit) $14.95
GM 10046089 valve cover gaskets $9.95 each
GM 12558060 Vortec heads assembled with 1.940" intake / 1.500" exhaust valves, single springs for max 0.450" lift, retainers and keepers $249.75 each
Scoggin-Dickey #BG4282010VE Barry Grant Road Demon 625 cfm vacuum secondary carb $339.95 or my personal favorite, the Rochester Quadrajet Scoggin-Dickey #E1901 Edelbrock 750. $449.95. Don't let the 750 throw you, it's not too much carb due to the tiny little primaries for excellent mileage and throttle response and the huge secondaries for power when needed.
Crane 100052 hydraulic camshaft (not listed in Scoggin-Dickey catalog, but could probably be sourced from them on special order. I'm just trying to source all parts from one supplier) Vortec heads are limited to 0.450" lift with supplied springs and this cam has 0.454" lift, talk with the tech guys at Scoggin-Dickey to find if this cam should be ground with a little less lift to work with stock Vortec springs, retainer/seal clearance.)
By the way, you mentioned 1.6 rockers on the exhaust. You won't need them with the Vortec heads. 1.6 rockers are used to crutch-up poor-flowing exhaust ports in relation to intake ports and the Vortec heads are well-balanced as cast. You'll see that some cams for the SBC are ground on a dual pattern, more lift and more duration on the exhaust side and again, this is to crutch-up the poor-flowing (relative to the intakes) stock Chevy exhaust ports. You also won't need any more lift than 0.450"/0.454" with these heads in a street application with mild track time. They flow so well that you don't need an excessive amount of cam lift to crutch them up like you might need with stock OEM Chevy castings.
Scoggin-Dickey #CRA99377-16 Crane High-Intensity lifters. $119.95 set of 16. These are fast-bleed lifters that produce a variable duration effect. At lower rpm's, these can reduce running duration by 6 to 10 degrees and decrease valve lift by 0.020" to 0.030". This controlled oil pressure increases cylinder pressure and performance in the lower rpm range without sacrificing duration and lift in the upper ranges. Somewhat like having your cake and eating it too. You may be able to run a stock converter with this cam if using these lifters. Talk to the tech guys at Crane.

Assemble the motor with the pistons 0.012" down in the bore at TDC. This will give you a squish of 0.040" using the 0.028" compressed head gaskets and will allow you to run pump gas without detonation at the calculated 9.65:1 compression ratio with the 64 cc Vortec heads and 12 cc KB pistons.

Set initial timing at the crank at 12 degrees and re-curve your distributor for total initial and centrifugal timing of 36 degrees, all in by 2,800-3,000 rpm's. Adjust fuel pressure for 5 1/2 to 6 lbs at the carb inlet. Degree the cam according to the instructions from Crane. Include a way to advance or retard it by 4 degrees after you have the motor running (offset dowel or whatever). That way, you can tailor the cylinder pressure higher or lower according to what you think you need.

Scoggin-Dickey Chevrolet website/catalog....
www.SDPC2000.com

O.K., the old tech guy is tired from all this and is going into the other room for a nap :)

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I LIKE IT ALL EXCEPT FOR THE HEADS.I WOULD TRY A SET OF DART IRON EAGLE S/S HEADS ,AND THEN GO WITH A SET OF SPEED PRO HYPEREUTECTIC PISTONS PART #H631CP.YOU WILL LOOSE ABOUT 3/4 OF A POINT ON COMP. RATIO BECAUSE OF THE CHAMBER SIZE BUT IT STILL SHOULD WORK FINE.AS FOR DEGREEING THE CAM I SAY JUST PUT THE CAM IN (STRAIGHT UP).THIS IS A DAILY DRIVER ANYWAY.GOOBLE,GOOBLE.

Erik, is that a nice way of saying you like the cam but everything else sucks? :eek: :LOL:

Quote:

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Originally posted by techinspector1
Erik, is that a nice way of saying you like the cam but everything else sucks? :eek: :LOL:

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NO I DO LIKE EVERYTHING ELSE.I WANTED HIM TO LOWER THE COMP. RATIO THAT WAY HE COULD RUN ANYTHING IN IT FOR GAS AND NOT WORRY ABOUT DETONATION.THE REASON I SAID TO GO WITH THE DART S/S HEAD WAS THAT WAY HE COULD ORDER THEN AND RUN UP .510 LIFT AND NOT DO ANYTHING BUT BOLT THEM ON.

That's why the tight squish. Should run fine on pump gas with no detonation.

Quote:

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Originally posted by techinspector1
That's why the tight squish. Should run fine on pump gas with no detonation.

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I WAS THINKING THE GASOLINE OCTAIN RATING MIGHT NOT BE AS GOOD OVER THERE.

Tech1, while you are thinking about cams, let me ask a question. Unfortunately I did not take your short course until my 350 engine build was past the assembly point. Anyway I did not deck the block so I assume the deck height is about 0.025" and I have used the standard gasket for about 0.039" with shaved 882 heads to give 73 cc pockets and flat top eyebrow pistons as 4.030" bore. I am satisfied the C.R. will be low enough that even without much quench I will be able to run with 87 or 89 octane. My question is the cam I chose does not seem to be in the Crane catalog anymore (at least I can't find it online) and the box had two numbers on it. The old number on the box is #10010 but it has a pasted-on label marked "10010" AND in larger numbers "140072", 0.050 DUR I 194 X 204. The card that came with the cam says:

Intake @cam 0.265 @ valve 0.398"
Exhaust @cam 0.280 @ valve 0.420"

@0.005
Intake 22 BTDC 58 ABDC Adv. Dur. 260
Exhaust 71 BBDC 19 ABDC Adv. Dur. 270

@0.050
Intake 10 BTDC 24 ABDC Adv. Dur. 194
Exhaust 39 BBDC 15 ATDC Adv. Dur. 204

I realize this is a very conservative low rpm torque cam, but (!) when I run the rpm numbers for cruisin' on two lane black top roads in the local area with a 3.55 rear ratio and a 700R4 4th OD gear of 0.7, I get 1446 rpm at 50 mph and 1591 rpm at 55 mph (235/75/R15 rear tires). It seems to me that I need torque in the 1500 rpm range to avoid downshifting to 3rd or lugging in OD. I am hoping the low gear of the 700R4 will give a good launch since the 700R4 has a lower 1st gear than the TH350, so the problem is to maximize torque in the 1500 range. Now here is the question. I have both 1.5 and 1.6 roller tipped rockers of the simple type from Speedway. IF I RUN 1.6 ROCKERS ON BOTH INTAKE AND EXHAUST WITH THE 882 HEADS I WILL GET 0.424" INTAKE LIFT and 0.448" EXHAUST LIFT. This is still a very conservative lift and the 882 heads seem to offer little flow beyond 0.400" valve lift, so the question is whether it will help or hurt to use the 1.6 rockers? Will the extra lift and short duration and lack of quench lead to detonation on 87 octane? Bottom line, should I use the 1.6 rockers to get a little more torque or will this lead to worse detonation on cheap fuel? I have both a Performer RPM manifold which I am going to remove and a Performer EPS which I think is better for low rpm. I guess I can start out with the 1.5 roller-tip rockers and then experiment with the 1.6 rockers, but I wonder if the 1.6 rockers will help much with only 882 heads or lead to worse detonation on cheap fuel? It also would be easy at this point to replace the head gaskets for the thin set you mention above. Overall I wonder if most folks realize how low the rpm gets in OD? In retrospect I guess I should have gone to a 3.70 rear gear but I can't afford to make that change unless I find out the OD really bogs with the 3:55. I had a terrific ride recently with a guy about 3 miles away who has just finished a Gibbons '32 highboy and he seems to get good mileage over 20 mpg with a 3.23 rear and a TH350 which only has a 1.0 high gear. Maybe there is no way around expensive trial and error but maybe the light weight of the '29 will make this no problem after all? Sorry to test your patience. I just have to get the car on the road because all this speculation is uncertain, but you are the closest I know to a "brain dyno".

Don Shillady
Retired Scientist/teen rodder

Well in edit mode it was good for me at least to go over all of this and now I realize that I probably will not be in OD at 50 mph but in 3rd with a pretty zippy 3.55 overall gear so probably I should have installed a 3.7 rear gear but I am just going to have to live with the idea that the OD will only be useful for the Interstate! Still that leaves the question for Tech1 as to whether the 1.6 ratio rockers will do me any good on this setup?

Quote:

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Originally posted by Don Shillady
Tech1, while you are thinking about cams, let me ask a question. Unfortunately I did not take your short course until my 350 engine build was past the assembly point. Anyway I did not deck the block so I assume the deck height is about 0.025" and I have used the standard gasket for about 0.039" with shaved 882 heads to give 73 cc pockets and flat top eyebrow pistons as 4.030" bore. I am satisfied the C.R. will be low enough that even without much quench I will be able to run with 87 or 89 octane. My question is the cam I chose does not seem to be in the Crane catalog anymore (at least I can't find it online) and the box had two numbers on it. The old number on the box is #10010 but it has a pasted-on label marked "10010" AND in larger numbers "140072", 0.050 DUR I 194 X 204. The card that came with the cam says:

Intake @cam 0.265 @ valve 0.398"
Exhaust @cam 0.280 @ valve 0.420"

@0.005
Intake 22 BTDC 58 ABDC Adv. Dur. 260
Exhaust 71 BBDC 19 ABDC Adv. Dur. 270

@0.050
Intake 10 BTDC 24 ABDC Adv. Dur. 194
Exhaust 39 BBDC 15 ATDC Adv. Dur. 204

I realize this is a very conservative low rpm torque cam, but (!) when I run the rpm numbers for cruisin' on two lane black top roads in the local area with a 3.55 rear ratio and a 700R4 4th OD gear of 0.7, I get 1446 rpm at 50 mph and 1591 rpm at 55 mph (235/75/R15 rear tires). It seems to me that I need torque in the 1500 rpm range to avoid downshifting to 3rd or lugging in OD. I am hoping the low gear of the 700R4 will give a good launch since the 700R4 has a lower 1st gear than the TH350, so the problem is to maximize torque in the 1500 range. Now here is the question. I have both 1.5 and 1.6 roller tipped rockers of the simple type from Speedway. IF I RUN 1.6 ROCKERS ON BOTH INTAKE AND EXHAUST WITH THE 882 HEADS I WILL GET 0.424" INTAKE LIFT and 0.448" EXHAUST LIFT. This is still a very conservative lift and the 882 heads seem to offer little flow beyond 0.400" valve lift, so the question is whether it will help or hurt to use the 1.6 rockers? Will the extra lift and short duration and lack of quench lead to detonation on 87 octane? Bottom line, should I use the 1.6 rockers to get a little more torque or will this lead to worse detonation on cheap fuel? I have both a Performer RPM manifold which I am going to remove and a Performer EPS which I think is better for low rpm. I guess I can start out with the 1.5 roller-tip rockers and then experiment with the 1.6 rockers, but I wonder if the 1.6 rockers will help much with only 882 heads or lead to worse detonation on cheap fuel? It also would be easy at this point to replace the head gaskets for the thin set you mention above. Overall I wonder if most folks realize how low the rpm gets in OD? In retrospect I guess I should have gone to a 3.70 rear gear but I can't afford to make that change unless I find out the OD really bogs with the 3:55. I had a terrific ride recently with a guy about 3 miles away who has just finished a Gibbons '32 highboy and he seems to get good mileage over 20 mpg with a 3.23 rear and a TH350 which only has a 1.0 high gear. Maybe there is no way around expensive trial and error but maybe the light weight of the '29 will make this no problem after all? Sorry to test your patience. I just have to get the car on the road because all this speculation is uncertain, but you are the closest I know to a "brain dyno".

Don Shillady
Retired Scientist/teen rodder

Well in edit mode it was good for me at least to go over all of this and now I realize that I probably will not be in OD at 50 mph but in 3rd with a pretty zippy 3.55 overall gear so probably I should have installed a 3.7 rear gear but I am just going to have to live with the idea that the OD will only be useful for the Interstate! Still that leaves the question for Tech1 as to whether the 1.6 ratio rockers will do me any good on this setup?

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IF THIS IS FOR YOUR( PARADE CAR) JUST PUT PREMIUM GAS IN IT AND DON'T WORRY ABOUT IT.

Well that may be the way it works out since my wife is not too keen on an open car anyway, but I wish I had joined the Forum 6 months earlier and then I could have built the engine Tech1 described for Lobster. So Erik what do you say about the 1.6 rockers? I guess for now I will use the 1.5s first for a slightly gentler break-in and then use the 1.6 rockers after everything is running OK, but even at 0.454" lift on the exhaust that is pretty mild, eh?

Don Shillady
Retired Scientist/teen rodder

Quote:

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Originally posted by Don Shillady
Well that may be the way it works out since my wife is not too keen on an open car anyway, but I wish I had joined the Forum 6 months earlier and then I could have built the engine Tech1 described for Lobster. So Erik what do you say about the 1.6 rockers? I guess for now I will use the 1.5s first for a slightly gentler break-in and then use the 1.6 rockers after everything is running OK, but even at 0.454" lift on the exhaust that is pretty mild, eh?

Don Shillady
Retired Scientist/teen rodder

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YES,IT IS A VERY MILD CAM BUT IF YOUR WIFE IS LIKE MINE SHE WOULD NOT LIKE AN ENGINE IN A CAR WITH TO ROUGH AN IDLE MEANING A LARGER CAM.THE 1.6 CHANGE WILL GIVE YOU A LITTLE MORE LIFT.IF YOU DON'T LIKE IT YOU CAN ALWAYS CHANGE THE CAM TO A LARGER CAM DOWN THE ROAD.WHAT DID YOU SAY THE CAR'S WEIGHT IS?

I'm just guessing from other posts at about 2500 pounds. I plan to actually weigh it at a commercial scale when I get on the road. So you are implying I could use the 1.6 rockers and then if it pings, go to 93 octane? Again I guess I would try the 1.5s first and then play around with the 1.6 rockers. Originally I wanted something like a Comp Cam XE-252, but surprisingly my engine builder refused to use a Comp Cam so I picked a mild Crane cam with just a little more lift than the stock "929" 300 HP (flywheel) cam. Actually the whole reason behind this was I remembered a Nova my dad had with a 350 and to me that was wildest stock ride I had encountered and if I get back to that I will be content! I considered a Comp 268 with Rhodes lifters but as you say I doubt if my wife would have liked the extra clicking of the lifters, so now I don't want to change much except to just use the best combination for low rpm torque using parts I already have. Well thanks for listening. I am learning from the discussion although maybe slowly and talking myself into using the 1.5 rockers at first.

Don Shillady
Retired Scientist/teen rodder

Quote:

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Originally posted by Don Shillady
I'm just guessing from other posts at about 2500 pounds. I plan to actually weigh it at a commercial scale when I get on the road. So you are implying I could use the 1.6 rockers and then if it pings, go to 93 octane? Again I guess I would try the 1.5s first and then play around with the 1.6 rockers. Originally I wanted something like a Comp Cam XE-252, but surprisingly my engine builder refused to use a Comp Cam so I picked a mild Crane cam with just a little more lift than the stock "929" 300 HP (flywheel) cam. Actually the whole reason behind this was I remembered a Nova my dad had with a 350 and to me that was wildest stock ride I had encountered and if I get back to that I will be content! I considered a Comp 268 with Rhodes lifters but as you say I doubt if my wife would have liked the extra clicking of the lifters, so now I don't want to change much except to just use the best combination for low rpm torque using parts I already have. Well thanks for listening. I am learning from the discussion although maybe slowly and talking myself into using the 1.5 rockers at first.

Don Shillady
Retired Scientist/teen rodder

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I WOULD TRY THE 1.5 ROCKERS AND IF YOU WANT LATER ON TRY THE 1.6 ROCKERS.I WOULD TRY AROUND 89 OCTANE FOR A STARTING POINT.I WOULD THINK IT WOULD RUN JUST FINE ON THE 89 OCTANE.

Don, I think you're worrying needlessly. Use the 1.5 rockers and fire it. For initial start-up and cam break-in, you want as little pressure on the lobes as possible and the 1.6 rockers would increase the pressure by squeezing the springs tighter. Change to the 1.6 rockers later after you have 200-300 miles on the motor if you want to.

Worst case scenario on the deck height is that the pistons are in the hole about 0.035" which would yield a c.r. of 8.65 with 7 cc's in the eyebrows and an 0.039" gasket. Your engine builder should have a record of the deck height.

Anyway, like I said, don't worry about it. The motor will make plenty of torque just off-idle to pull that lightweight little roadster. The cam you're using is just one notch off bone-stock and Chevy built millions of motors like this with excessive piston-head clearance and low static c.r. It's gonna be smooth as silk and pull hard. :)

Tech1, Thanks! You confirmed what I thought about starting out with the lower ratio rockers since Speedway even sells 1.3 rockers for break-in. I got the safety loop welded in for the driveshaft, the hand brake lines set up and the trans cooler on the side of the frame with a DeRale trans pan so I am getting ready to cut the holes in the floor for the gearshift and handbrake. I am impatient but making slow progress. I also got a custom stainless gas tank so I hope to get the floor-fenders on before the really cold February weather. I am sorry to work you on this question but now I am more confident about starting with the 1.5 rockers and then experimenting with the 1.6s later.

Don Shillady
Retired Scientist/teen rodder

The question is, who do i believe about the heads???

i was looking into some after market heads (such as the Dart and others) but they added up to be around $1000, where as the vortec are around $500.

is it worth the extra bucks, or would they be better spent else where?

The q-jets do sounds the best (just a pain to tune apparently) as the low torque is better. maybe i use the $500 i save by getting vortec heads, and put it towards a quad weber 2barrel stack. even though the initial cost of buying 4 weber si s high, ive heard you can get much better torque and marginally better fuel economy for the same top end power, when compared to an equivalent 4 barrel (thats if they are all tuned PROPERLY)

too many choises

oh and over here the pump gas is around 90, but for extra $$$ you can get 95 or so

Quote:

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Originally posted by lobster
The question is, who do i believe about the heads???

i was looking into some after market heads (such as the Dart and others) but they added up to be around $1000, where as the vortec are around $500.

is it worth the extra bucks, or would they be better spent else where?

The q-jets do sounds the best (just a pain to tune apparently) as the low torque is better. maybe i use the $500 i save by getting vortec heads, and put it towards a quad weber 2barrel stack. even though the initial cost of buying 4 weber si s high, ive heard you can get much better torque and marginally better fuel economy for the same top end power, when compared to an equivalent 4 barrel (thats if they are all tuned PROPERLY)

too many choises

oh and over here the pump gas is around 90, but for extra $$$ you can get 95 or so

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THE DART S/S IRON EAGLE HEADS SELL FOR AROUND $570 WITH VALVE SPRINGS IN THEM GOOD TO .510. SEE COMPETIONPRODUCTS.COM OR 1-800-233-0199.

Lobster, here is an old thread on the Vortec heads. Keep in mind that the intake manifold is different for those heads but that is no big deal.

http://www.clubhotrod.com/forums/sho...2404#post72404

Don Shillady
Retired Scientist/teen rodder

.. Did this Range Rover mudder ever get built with Chevy 350"?

Boy, check the dates on this thread as from quite a while ago. And yet I am replying to keep this thread going with some of Tech1's best work. Time does fly by but I note that it was only on 9/19/2012 that we actually fired my engine described above so maybe the Range Rover is still a work in progress. Since I am new to my present neighborhood I was unaware that less than a mile from my home on a back road there is Progressive Automotive (Ashland, Va) with Proprietor Mr. Chester Houtaling. He runs a complete engine shop including a dyno and it took me several years to eventually meet him. Anyway he visited my garage and helped me time an old points type distributor with a Pertronix kit which was the only distributor I could find to slip between my motor and the fiberglass Bebops firewall. Anyway I reread the great advice from Tech1 above and he recommends an initial timing of 12 degrees static. Chester Houtaling came up with 8 degrees on my engine with the mild cam and 1.5 rockers using 93 octane gas to start. Since then I have run 89 and 87 octane without any noticeable pinging. Boy, first gear of the 700R4 is really "sudden" even with a 3.55 rear but I may have to go to a smaller rear tire size to get the OD to kick in at 55 mph. Sooo, my only question here is to note that my Chiltons Spec book for a 1976 Corvette lists 6 degrees for the lowly L-48 165 HP motor but 12 degrees for the L-82 205 HP motor. I had some overheating problems which were finally traced to a blockage in the Walker Cobra radiator but now I am running a 180 degree thermostat (in winter air) in a Zip Riser water pump unit. So far no problem with the flat tappet cam. Chester and I ran in the cam at 2000 rpm for 20 minutes with the 8 degrees and the vacuum advance blocked off using Joe Gibbs breakin oil. A leaking oil filter gasket caused a refill with Brad-Penn SAE30 with high ZDP for further breakin. I will switch to Amsoil-15-40 after 3000 miles. The question is maybe I should retune the initial timing to get the engine to run a little cooler or is 8 degrees in the "just right" range? There is a guy in Ashland (unknown to me) without a garage who is doing a body-off restoration of a Range Rover in his side yard and a number of people are rooting for him to make progress while we pass him by seeing the bare bones on sawhorses. Anyway I can't brag because my engine sat unfired almost seven years so it was a really good exerience to have it kick off in September. Thanks for the excellent discussion Tech1!

Don Shillady
Retired Scientist/Teen Rodder