Quote Originally Posted by hpwdboss1
We're starting to research parts for an engine build with very specific rules for the class. We are limited to a 650 cfm carb, 5500 rpm (msd box), all iron heads and manifold, no roller valve train components, and a 500 c.i. limit. Gasoline is the fuel. This will be in a tractor pull so there will be little or no on/off throttle driving.
Assuming a possible max of 750 cfm through this carb body, can we utilize more than 460 inches or will the cfm restriction negate the benifits of more c.i.d.?
Are there "better" castings to use for heads and intakes, and if so, what casting #'s etc. should we be seeking?
Thanks in advance for any help.
You truck puller guys have all kinds of neat competition throughout the midwest...but no broad-reaching rules, meaning that from one club to the next, the rules change.

Does this class have a vacuum rule or any other rules that we need to know about?

With what little I know about truck pulling (and your specific rules), I would probably opt for a C8VE, C9VE or D0VE cylinder head casting (all are basically the same configuration). The port size of these castings, combined with the performance prep mods that you can do to them, make for a very good cylinder head choice for running a sustained 5500 rpm (max) on a 460 cube motor.

Others may point to the D0OE-R iron Cobra Jet cylinder head, but that head does not really come alive on a 460 until around 5000 rpm. Besides, I think that the tiny 650 750 carb rule limits potential port velocity when combined with the gargantuan-ported iron CJ heads.

If you were to build a 498 cube deal (4.11 offset stroked oem crank, 6.8 rods and 1.45 c/h pistons), the C8-C9-D0VEs could work and so could the CJ's. Just bear in mind that if you grenade the motor and the CJ head is taken out in the destruction, well, good luck finding another one.

At this point I would suggest starting with the .030-.060 over 460 and well ported D0Ve heads.

Paul

p.s.: Also,check with Bret Powell of PFC Engines in Missouri. He has one of the winningest iron BBF pulling trucks around, runs a sustained 8500 rpm for 27 seconds at a time.

pps: Thx Erik.