Thread: 355 cam choice

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That puts it in a better perspective for me, thanks. Maybe I'll find someone to buy the couple sets of heads i have and put the proceeds towards some new heads, anyone know what ideal heads i should go with on a budget of $1000?

Profiler heads are probably the best aluminum head for around $1000. Do not even consider ProComp heads no matter how attractive the cost--absolute junk.

www.profilerperformance.com/sbc-heads-176.html

Iron Vortecs are less expensive and a very good flowing head but you will have to use a Vortec intake manifold.

www.summitracing.com/parts/SUM-151124/

Originally Posted by 80ZJoe

That puts it in a better perspective for me, thanks. Maybe I'll find someone to buy the couple sets of heads i have and put the proceeds towards some new heads, anyone know what ideal heads i should go with on a budget of $1000?

PBM iron heads loaded for under 800.good head for the money could look in to them iron killer heads brodix bro1020001 or the RHS in iron

I've looked at a ton of SBC heads and am impressed with the RHS (Racing Head Service) cast iron heads for the money. Let's assume you can zero deck the block to the pistons for zero piston deck height. Let's further assume you have 6cc's in the flat-top piston eyebrows, a run-of-the-mill Fel-Pro composition head gasket that compresses to 0.040", 1 5/8" long tube headers through the mufflers of your choice, an Edelbrock RPM or Weiand Stealth intake manifold mounting a 750 CFM vacuum secondaries carb of your choice, these heads....
http://www.summitracing.com/parts/RHS-12301-01/
(making a static compression ratio of 9.35:1 with the flat-tops), and this cam & lifter kit....with the cam installed 2 degrees advanced....
http://www.summitracing.com/parts/CRN-100132/
I don't like to spec flat tappet cams any more, but will use one here just for simplicity and because it is relatively cheap. Follow all the precautions given in the link at the bottom of this post.
I have factored the published flow of these RHS heads by 0.95 in order to present a realistic head flow. Sometimes the manufacturers fluff up the flow a little with tricks of their own, like larger bore pipes than the engine builder will be using. For instance, when's the last time you saw a 4.200" cylinder on a 350 Chevy??? Anyway, I feel that this DynoSim is pretty near to realistic to what a real motor would generate on a real dyno. I've done several hundred of these exercises now and I think I have a pretty good feel for reality.
RPM HP TQ
2000 146 383
2500 186 390
3000 237 416
3500 295 443
4000 346 455
4500 387 451
5000 421 441
5500 430 409
6000 410 359
Peak volumetric efficiency 93.7% @5000
Peak BMEP 192.9 @4000
This motor makes some pretty good cylinder pressure as evidenced by the BMEP, so zero decking the block for a 0.040" squish is MANDATORY if you expect to operate the motor on pump gas. No whining please. Just do it. Use a 2500 stall converter and 3.73:1 rear gear and you'll tear the tires off. This is one of the better 355 street/strip motors I have DynoSimmed. Great cylinder heads for a 355, they really pack the cylinders.
http://www.crankshaftcoalition.com/w...ips_and_tricks
For ignition timing, establish TDC on your damper with the timing tab you will be using. Here's a tutorial from Isky as to how to do it as you are assembling the motor and finding TDC to degree the camshaft....
http://www.iskycams.com/camshaft.php
If the damper won't degree properly, the inertia ring has more than likely slipped on the hub. Over time, the elastomeric material that separates them breaks down and will sometimes allow the inertia ring to move in relation to the hub. If that has happened, you really need to rebuild or replace the damper. I always use an OEM damper because the bore is correct for a press fit onto the snout of the crank. Some aftermarket damper hubs are bored either too tight or too loose. If the fit is too loose, the harmonics that are set up in the crank each time a cylinder fires will not be dampened properly from the hub to the inertia ring and crank failure can result. If yours needs rebuilding, send it to Damper Doctors to be rebuilt or if you don't have one, call 'em up and order the correct rebuilt damper for your application.
http://www.damperdoctor.com/Merchant...egory_Code=CHE
Anyway, start with 14 degrees at the crank and 20 degrees centrifugal. Use a kit from Summit to tailor the curve. Also, install a Crane adjustable vacuum timing cannister and a Crane limiter plate. The HEI cannister is 99600-1 and the plate is 99619-1.

Thanks, I'll search the local shops first to see what they have or can get cause i hate ordering parts from the internet and heads would be imaginably pricey for shipping. But i'll keep yas posted about what they have. Here is a pic of the pistons i'm using, what should i do about the surface rust on the deck? it's not as bad as it looks from the pic but is there anything i can do myself without ruining the deck or would i have to have a machinist shave it or something? It's not pitted so i don't think it would be a hard fix.

Awww, you've messed up already. Those are cheapo rebuilder pistons with a 1.540" compression height. Geez, I wish there was some way that you fellows knew to ask someone who knows this stuff before you buy this junk. To get to zero deck now, you'll have to remove about 0.045" from the decks instead of 0.025" if you had used the correct 1.560" pistons. Then the decks start gettin' a little thin and may not hold a head gasket and you have to whittle the heck out of the intake manifold to get it to line up and yadda yadda.

If it were mine, I'd remove those pistons and sling 'em over the fence, than get on the horn and order some decent pistons like these that would make 9.35:1 with a 72cc head....
http://www.kb-silvolite.com/kb_car/p...tails&P_id=156

But hey, it's your motor, do as you wish. Pat McCarthy may have cut some decks this thin in the past. Maybe he can tell you what to do.

your talking 045 off the deck thats a bit but. i have cut off 030 on the sbc i care not to cut any blocks too much .on the race blocks i have cut 100.off the deck of a hurt 10.200 race block there just thicker then a 9.800 deck just more iron .but.. my mill is made for cutting big heavy cuts still takes a long time and wears the cutter on the wheel .so it cheaper to get a better CH piston so there s on need for a heavy cut some cast piston are very hard to get to a O deck

That sucks, I didn't technically mess up i was lied to lol, i was told they were really good pistons.... f***ing BS

Tech - those last heads and pistons you recommend would give an effective combustion chamber of 79cc right (72cc + 7cc)? Does your calculator give the dynamic CR with that combo?

I'm getting 8.75 DCR with my homegrown calculator with the cam intake closing at 36 degrees ABDC . . .

tech has a new dyno program he may have a dynamic sim on it ? i know he did use the KB pistons that is the one i use till i get $500 for my new dyno program

Originally Posted by SBC

Tech - those last heads and pistons you recommend would give an effective combustion chamber of 79cc right (72cc + 7cc)? Does your calculator give the dynamic CR with that combo?

I'm getting 8.75 DCR with my homegrown calculator with the cam intake closing at 36 degrees ABDC . . .

No, I have been using the Keith Black calculator for several years. I don't think it matters whose you use, as long as you stick to one calculator and know what kind of number it takes from that calculator to tolerate pump gas.

On the second line of post 19, you can see where I assumed 6cc's in the eyebrows. This would have been fairly accurate with a quality flat-top piston. I didn't have a clue as to what piston he had at the time I wrote that post, but was just swinging the bat through to see what we had. I further allotted 9cc's for the 0.040" gasket, so the entire volume would be 72 + 6 + 9 with a zero deck. If you figure an overbore of 0.030", you have 727cc's in the cylinder. 727+72+6+9=814. 72+6+9=87. 814 divided by 87=9.35:1 static compression ratio.

Using the KB calculator, if you enter 9.35, along with a 5.703" rod, 3.480" crank and 49 degree ABDC intake closing point (36 @ 0.050", advanced to 34 and with 15 added, which is what is called for by the calculator), you get a Dynamic Compression Ratio of 8.282:1, which is in the range of 8.00 to 8.30 that I shoot for on the KB calculator to tolerate pump gas.
http://www.kb-silvolite.com/calc.php?action=comp2

I just noticed that the KB piston I linked is actually 7cc's instead of 6cc's. There is probably 1 cc or more variance in the combustion chambers, so I'm gonna let it ride. It ain't rocket surgery.

Cool - I was wondering how the timing advance would affect everything and the 2 degrees alone wasn't making a big difference. The extra 15 degrees brings it into pump gas range as you said. THATS the factor that I haven't been considering.

Is there a rule of thumb as to how much timing can be added before everything is out of whack?? Seems like I have read posts suggesting as much as 36 degrees in some cases.

The main reason why on my build I am not using KB pistons is the design promotes carbon build up on the ring lands.Seems to be just a bad design.I spoke to Mahle some more to find you can run those pistons at 4.029 vs 4.030,one thousands tighter that limits or eliminates cold forge piston slap because of the coating.One tip they gave me was to NOT use anything like carb cleaner to clean the pistons before the install of them.That kind of cleaner lifts off the coating.Of course they are making claims the coating last for the long term where on another thread I had concerns posted.The piston/ring design on the Mahle hands down seal without any carbon build up.They also told me they don't build cast pistons or pistons without the coating.Yeah I think in this case I found the age old saying.............."You do get what you pay for".The Mahle of course costs more.

Wel i guess the funds are gonna go toward new pistons now

Originally Posted by SBC

Is there a rule of thumb as to how much timing can be added before everything is out of whack?? Seems like I have read posts suggesting as much as 36 degrees in some cases.

I'm not sure what your're asking, but if you're talking about how much you should advance or retard a camshaft to get the characteristics of the motor where you want them, a rule of thumb there is that if you have to advance or retard more than 4 degrees, then you have chosen the wrong cam.