Thread: Specs on my build

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Ok gentlemen,

Here are the specs on the build I'm planning. I am for the most part copying a build that was done at FastTimes motor works out of Illinios.

454 seasoned block .030 over with torque plate hone. Cast crank turned 10/10 and spin balanced. Stock rods with beams ground, arp bolts and balanced. TRW L2349 forged pistons with dome (I think this is a repro LS6 piston) Hastings rings.

Now the cam they used (which I have not purchased yet) is a Crower 247/251 @.050 and .579/.594 lift on 112 degrees lobe separation.

Question #1: good choice on cam?

Heads (which I have obtained, but not done a thing with yet) are 781 GM heads with 2.25 intake 1.88 exh Manley Race Flo valves. Mild porting with gasket match to intake and cleaning up ports @the valve. Valve springs with seat and nose pressure of 125 and 330 pounds. 1.7:1 Comp cams roller tip rockers.

Question #2: any suggestions on the heads...Im thinking maybe intake valves are a little too big? Maybe go with 2.19? Or does anyone recommend an after market oval port head that can keep this thing on pump gas (118cc 781's put it at about 10:1 right now)

For a carb they used a Holley 850 cfm double pump (part # hly 4780), and didnt say if is had vaccum or manual secondaries.

Question #3: A little too big of a carb? Vaccuum secondaries I am thinking is the way to go?

Intake manifold they used was a Holley strip Dominator intake Part # hly300-4b.

Question #4: Is this a good manifold for this build? I suspected a dual plane may be more approprite for a car that is mostly street, with the 2-3 times down the track it may take just for kicks?

Finally ignition used is a Mallory comp 9000 & coil Part # Mly 9048201.

Question:#5 Any other recomendations? I have no ignition experience, and all other engine builds I have done have always just used a GM hei unit and rebuilt it with premium parts.

They show a Dyno sheet on this build and it states with 40 degrees timing, 77 and 78 main jets in the primaries and secondaries, it pulled 500 ft.lbs @ 4800 rpm; and 512 hp @ 6200.

Now anybody can print dyno results and I am not experienced enough to know if this is accurate.

I am putting motor in a 66 Chevelle SS that will be mostly street,and occasional strip, but is by no means my daily driver. I was planning on anywhere from a 3.73: to 4.11 rear end 12 bolt running a th400 trans with I am guessing 2500-3000 stall. Any recomendations on this are welcomed.

I beleive this time I gave you guys all pertinant info to make good recomendations and comments. So fire away; of course like most people, I want to produce the most "streetable" power out of this engine, and Im thinking the place to achieve this are the heads.

To you experienced guys out there...your knowledge is invaluable and if you could take the time any recomendations, comments and info from you is very much valued and appretiated.

30-A Rider.For a carb they used a Holley 850 cfm double pump (part # hly 4780), and didnt say if is had vaccum or manual secondaries.
If it's a double pumper then it is a manual secondary carb. But according to the Summit catalog if it's a 4780 its a 800 CFM double pumper carb. Summit list the 4781 as a 850CFM double pumper.

I think your heads are just fine, might be just a hair much on the cam, I'd definantley go with a dual plane intake.
I think the carbs a bit much 750 would be my choice, I don't think 40 degrees timing on pump gas is realistic ( we ran 38 total on mine and that was a alky motor), of course take this all with a grain of salt as I am by no means an expert engine builder, just an old fart with a lot of experiance (LOL)

yeah i think the cam is too big... but i'm not an experianced engine builder like some other people on here that's just my 2 cents i've got a book that says "210-216@.50 is good for an mildly modified engine were you still want your power brakes" so i would cut down on the cam a lot (i could be wrong and i wouldn't listen to me as much as the other people here)

You'll get all kinds of recommendations on this one. Here's what I built in my last 454 for my A-bone sedan. It was an LS-4 that came from a Caprice station wagon. I'm not claiming that it's ideal, but it ran like a scaldedassape.

Comp Cams 292 Magnum (11-213-3) 244/244, 0.550/0.550, 110 lobe centers
Holley Street Dominator intake
Holley 850 double pumper
Mallory Unilite & super-coil
3944290 Oval port heads, no mods except a 3-angle valve job. 2.06/1.72 valves. I don't remember the CR, but it was a little over 9.0:1
Crank was stock (forged) and the rods were stock. I used Hypereutectic pistons.
4-speed top-loader w/ 4.10 gears

I'm not sure this engine was optimized, but I ran low 12's all day long on street tires and closed exhaust.

I think your heads are a little big for the street, but since you have them, I think you can develop a combo that will work.

I'd be looking at a Comp Cams Magnum Hydraulic Roller (290HR) 232/232, 0.578/0.578, 110 lobe centers, but I would confirm with Comp Cams before making the purchase. You might also check with a couple of other cam manufacturers to see what they recommend. Granted, they're trying to sell bumpsticks, but I've generally got good info from their tech lines. The dual-plane manifold is a good idea, perhaps an Edelbrock Air Gap 2 with a Speed Demon 850. . A .60-over 454 at 6000 rpm calculates out to about 800 cfm. (460 x 6000)/3456 = 799 cfm, so 850 is within the range.

Just some thoughts.

Much thanks to those who have contributed so far.

Anyone else? I was hoping I would get a lot of reply's on this thread.

First....cam

this is a good grind....it will make some power....good gas and conservative timming...or it will detonate...start with 26 deg total and bump it 2 deg at a time till you find the sweet spot....

second....heads... they are fine...sounds like you got a good set...

third....card...850 double pumper is good for street and/or mild tract use and more strip and you'll need a bigger....personally I'd opt for a 950+cfm

fourth.....the strip dominator will work best with that cam but, for the most part I'd go with the dual plane if you going to do a lot of street driving....you'll gain some low-end torque but at the cost of upper HP....

fifth.....the hei you use will be fine...add a MSD or crane ignition box to compliment it....

rear suspension upgrade.....to help it stick

Sounds pretty good just as it is....what are you looking for mostly?? You say mostly street, so do you want lots of torque at the expense of a little upper RPM Horsepower? (That's me) First, the heads are great...I use them too, but with the 2.19/1.88 valves...2.25 intake is OK, but not needed for the street, but if they're already done, use them. It's not the valve size you have to worry about so much, its the runner size, and the 781's are great for street use (or race for that matter) Pistons are good, I used them too..they are a closed chamber piston, but will work with your open chamber heads...with normal deck height (.020 or .025) and standard thickness gasket (.040) and assuming your chambers are about 118 - 120 cc, you should be around 10.3 or so on c/r.....getting up there for pump gas, but still OK if you're careful...make sure you use the highest octane you can get at the pump, and dont go crazy with your ignition timing. I would go with a dual plane intake for the street, RPM is great and the air gap looks a little cooler too! Dont go bigger than an 850, even that's not needed....a plain old 3310 Holley will be all you need...(750 vacuum sec.) If you want the status of a "double pumper", get a 750 or 850 at the most, in my opinion. Cam is a little big, but again, depends what you want...If you're going with flat tappet cam, I would stick with mid .500 lifts, and around 230 to 235 duration at .050, getting bigger than that will kill your vacuum (brakes?) and your low end torque...and I would go with 110 LSA, not 112...but that's just my liking...little lumpier idle with 110, quicker torque curve too. Email me for more cam suggestions if you want. As far as gears, I wouldnt go with 4:11's, you wont need them with all your torque...stay with 3:73's or lower for street use. Stick with HEI with modified curve for ignition, they work fine...update with MSD as Dr.Bowtie suggested if you want more spark. Good luck, sounds like you're on the right track. John

Ok most said cam was too big. I called comp cams and they gave me a recommendation. Now I am by far no cam expert, but I beleive what they recommended isnt too far off from what I originally had listed, but like I said when it comes to cam geometry I am an idiot. So any input again would be appretiated.

To review here is the cam I had originally listed:

247/251 @ .050
.579/.594
112 lobe


New cam listed by Comp Cams (note cam is same as used in Recon 496 motor and World 509 motor)

Xtreme Energy
240/246
.574/.578 @.050
110 lobe

30a rider.....that second cam sounds better to me....that's quite a change in duration (for the better) and I like the 110 LSA much better. Will definitely be torquier than your first choice. Nothing personal against Comp Cams, but I would get a couple other recommendations. Try a smaller place like Isky, or Howards Cams...they've been around forever, and they're all racers and engine builders. It's nice to get opinions from the source, and not from someone looking at a computer screen, just my opinion. My last few cams have been from Howard's Cams, and I couldnt be happier, but there are lots of others out there.

Johnny O or whomever,

SO again the cam most felt is too big. OK.

So the original cam was as follows:
247/251
.579/.594
112 LSA

Here are 2 possibilites suggested from Crane and Comp Cams:

Competition Cams
240/246
.574/.578
LSA 110

Crane Cams (Xtreme energy XE274)
234/244
.564/.571
LSA 111


Which of the 2 do you guys feel is in my best interest?

Or any other recommendations are welcomed. thanks gentlemen for your time and opinions

I like the latter of the two, the Crane....try one more thing...call Howard's Cams, 920-233-5228...speak w/ John or Scott, or anyone else for that matter. Tell them exactly what you have, and what you're looking for...be truthful and dont exaggerate anything. They'll set you up with something that will work great, and you'll love the price (You're paying for a lot of promotions with the other two) Ask them if #122441 would be a good choice...that's the one I would pick for you, but see what they say. That one is on a 112 LSA, but if you want it on a 110 or something else, they will grind it for you...still for less than the others. Ask them how the different LSA's will affect your engine, and see if that will work for you better. If you end up calling them, shoot me an email and let me know what they tell you, I would be curious. The rest of your combo sounds pretty good. I think a vacuum secondary carb would be good, but lots of others like the double pumpers... Vacuum will give you better mileage, but that is gonna suck either way, so dont base it on that!! Let me know how you make out. John

Ok Johnny,

I called howard and told them I was recommended by you and told them your suggestion. Mistake. The guy who I spoke with was not either of the 2 you recommended (said they were busy) I told the guy what I had and what I was doing with the car then told him what you recommneded and without hesistation he said yeah the cam #122441 is good and I should go with that. Now Im a little scared to do that cause the guy didnt ask one question of me and seemed to answer with no thought what so ever.

The specs are as follows if anyone would like to comment

234/240 @ .050
.540/ .540
112 LSA

HHaaa... well, I guess maybe they should put me on the payroll.... OK, I'll give a call tomorrow and talk to John...I have your specs here, I'll print them so I have them with me. But I would still rather that you speak with one of them, other than the one you did talk to. I know what you mean, it makes it sound like they didnt give any effort to find out anything. I still feel that this would be a good cam for you, but I would still get it on a 110 LSA, but that's just me. I like the tighter lobe center, but it makes for a little rougher idle..the tradeoff is getting to your torque curve more quickly, and a little more cylinder pressure. I'll email you with more info tomorrow. And getting more opinions is always a good idea too. Hang in there. John

I suggested a 110 LSA and the guy I was on the phone with said no way I could run anything power with a 110 LSA. The car is a 66 Chevelle and I want to stick with the drum brakes, but had planned to switch to power. Whada ya tink?