BBC Cylinder head Question

8SECNOVA · Post by **8SECNOVA** » Sat Feb 26, 2005 8:12 pm

First, I would like to say that it is awesome to see a forum where there are car guys who actually like to help other car guys with questions or dilemmas they have. That being said I have a question of my own. I am building a BBC for a pro street /strip car that I have. It is going to be at least 572 inches, and up to 632 inches. It will be a pump gas motor, with a sheet metal intake and two 4500’s. I know it sounds a little off the wall for a “street car” but I would like to make 8-900 H.P. My question is, would my best potential to make the most power be a big chief style head or a standard 24 degree head? Being that it is going to be around 10.5 - 11:1 compression, would it be a waste of time to use a head with that large of a runner? Also what do you guys think about the long strokes, and a wet sump system? Thanks for reading. Brian

Post by **ou812** » Sun Feb 27, 2005 2:15 am

Having done a few BB chevys, I can honestly say that the AFR cnc ported 335 or 357 head would be plenty for the HP range you are trying to reach. That being said, I would probably stick with the 572 as parts will be more readily available and cost should be better than a larger engine. Ofcourse drysump would be prefered if the cost is not a problem. Make sure you can find a pan and system that will fit in your chassis. If you really plan on running 91 octane and no race fuel mix, I would consider running the top ring on the piston down around .375 or so to keep it away from heat from occasional detontation. Good luck, hope this helped...
Brian

JOHNZ · Post by **JOHNZ** » Sun Feb 27, 2005 9:16 am

IMHO, engines for street/strip cars are challenging to build...you would have to compromise on one or the other....also, head selection, et cetera depends on the rest of the combination in your car (drivetrain, weight, backhalved car, et cetera..)

to answer your question, your best potential for more power would be with the Big Chief heads...it would be hard to get 10.5:1 CR with them though...also, I would imagine they would be a dog in low rpm...

Having said that, it does not mean that these heads would be the best choise for what you want to do..

sorry if it sounds confusing, with more info on the rest of the car and info on ts most frequent intented use (street or strip) would help us get you a better answer...

good luck...

8SECNOVA · Post by **8SECNOVA** » Sun Feb 27, 2005 9:54 am

The car is a 66 Chevy II. It is a full tube chassis car, with a four link. Weight is around 3200 lbs with me in it, with a big block. It has 31 x 16.5 ET street’s, and 4.11 gears. The car is being built primarily for the track, but it will be street driven also. Since the engine will be at least 572 inches, do you think the cubic inches will get it out of the hole (using big chief heads)? What do you consider low rpm? The convertor will be around a 4500 stall. I can get pistons made for the compression I need. I have already talked to some of the manufacturers. Hope this helps. Thanks again.

PWMAX · Post by **PWMAX** » Sun Feb 27, 2005 11:07 am

I personaly like the Canfield heads myself, for your deal obviously the 350cc head would get the nod, ported of course. i have gotten over 420cfm out of them, with a port around 365-370cc, which would work great on a 572. I would imagine your cam will be somewhat conservative, as its going to be a street pump gas deal, and these Canfields will work better for lower rpm tq, I know lower rpm is a subjective term at this level, but I have built engines exactly like your refering to, and am doing one as we speak, a 572, pump gas deal, the Canfield heads, and a moderately mild, solid roller. This is a proven combo, and will make 850hp on 92. World products also just came out with an interesting new semi "convential" head. 350cc port to start, rolled to 16 degrees, 2.30 inch intake, and an 80cc chamber. I would imagine with some port work, these will go 440 plus cfm, best part, is that they are WAY cheaper to run than a bigchief, and use regular stud rockers, and convential intakes. Obviously you need revised valve reliefs. It seems your budget doesn;t seem to be an issue, so, if you have it, then you can make 1000hp with bigchiefs if you went that route.

Frank
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