modified stock clarity

firebird · 01-02-2011, 04:52 PM

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.

Mark Markow · 01-02-2011, 08:58 PM

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.

firebird · 01-02-2011, 09:24 PM

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

Adger Smith · 01-03-2011, 12:30 AM

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

340Cuda · 01-03-2011, 11:18 PM

Quote:

Originally Posted by Adger Smith

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

Which one do most folks run these days?
Bill

Mark Markow · 01-04-2011, 10:19 AM

Quote:

Originally Posted by 340Cuda

Which one do most folks run these days?
Bill

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.

01-02-2011, 04:52 PM	#1
firebird Junior Member Join Date: Jan 2011 Posts: 52 Likes: 1 Liked 1 Time in 1 Post	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.

01-02-2011, 08:58 PM	#2
Mark Markow Senior Member Join Date: Apr 2008 Location: east hartford ct. Posts: 539 Likes: 0 Liked 9 Times in 3 Posts	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. __________________ Mark Markow 171 ss/tb

01-02-2011, 09:24 PM	#3
firebird Junior Member Join Date: Jan 2011 Posts: 52 Likes: 1 Liked 1 Time in 1 Post	Re: modified stock clarity thanks mark----I feel like you need a lawyer to understand the NHRA rule book ----mistakes are expensive

01-03-2011, 12:30 AM	#4
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	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 __________________ Adger Smith (Former SS) Last edited by Adger Smith; 01-03-2011 at 12:30 AM. Reason: sp