modified stock clarity
 

i have some questions on building a modified stock motor. i am looking at a b or c class and i am not clear on carburetor or a few other items. i also don't understand the cylinder head rule. pistons are another question. will somebody give me a little clarity on building a modified stock engine thank you.

Re: modified stock clarity
 

750 cfm carb you can check the list for legal carbs . heads and block need an o.e. casting number. aluminum in b , iron in c. if it's a chevy combo . most in b use either a 15 or 18 degree gm, but the sb2.2 head is also legal. c guys use the iron vortec heads most often.must be an inline valve head only. as far as pistons, pretty much anything goes.

Re: modified stock clarity
 

thanks mark----I feel like you need a lawyer to understand the NHRA rule book ----mistakes are expensive

Re: modified stock clarity
 

Legal carbs & Bore size by NHRA:

CLASSES
750 CFM
SS/BS, SS/CS, SS/DS,SS/TB, SS/TC, SS/TD, C/ED, ASR,
A/SR, B/SR, C/SR, B/EA, C/EA. D/EA, E/SM, G/SM.
CARB # PRI TB SEC TB PRI VEN SEC VEN
3310 1.687 1.687 1.402 1.463
4779 1.687 1.687 1.402 1.402
6109 1.687 1.687 1.402 1.402
6709 1.500 1.750 1.276 1.588
8156 1.687 1.687 1.402 1.402
9379 1.687 1.687 1.402 1.402
9645 1.687 1.687 1.402 1.402

Re: modified stock clarity
 

Which one do most folks run these days?
Bill

Re: modified stock clarity
 

most use the 4779 holley but barry grant makes a demon that is also legal. i'm using one. it works well out of the box. it's good place to start without having to send your holley out to someone for mods.