Carb size ?

Jeff Stout · 10-09-2020, 02:03 PM

A max size carb per rules for each motor combo. I know we no longer need carb numbers to be correct per engine. Any rule on how small a Qjet you can have? Asking to try a small cfm if legal.

GTX JOHN · 10-09-2020, 05:15 PM

Carbs still need to be the original Specs/Dimensions including boosters/Throttle blades. have

I prefer the Edelbrock Replacement Q Jets.
I have several in great shape and even NOS.!

I believe a 750 must replace a 750
and 800 replace a 800.

You can easily look down the throat to see the difference.

Believe it or not = I used to race a National Recording Holding 86 Ram 100 with
a Q jet.

Billy Nees · 10-09-2020, 05:18 PM

Quote:

Originally Posted by Jeff Stout

A max size carb per rules for each motor combo. I know we no longer need carb numbers to be correct per engine. Any rule on how small a Qjet you can have? Asking to try a small cfm if legal.

If you are still running the 307 roller combo, you must use an 800 CFM Q-Jet. Plus .005 or minus .015. Same carb that I have to use on my 301 Pontiac.
Just a bit of advice, don't listen to what some "previously employed by NHRA" people might have told you.

Billy Nees · 10-09-2020, 05:23 PM

Quote:

Originally Posted by GTX JOHN

Carbs still need to be the original Specs/Dimensions including boosters

Yeah, I wish that this were true John but look at all of the replacement Holleys that have "down-leg" boosters. The only thing that matters anymore is throttle bore and venturi size.

Jeff Stout · 10-09-2020, 05:49 PM

Thanks for the response. Saves my testing that idea.

Jeff Stout · 10-09-2020, 08:31 PM

Quote:

Originally Posted by Billy Nees

If you are still running the 307 roller combo, you must use an 800 CFM Q-Jet. Plus .005 or minus .015. Same carb that I have to use on my 301 Pontiac.
Just a bit of advice, don't listen to what some "previously employed by NHRA" people might have told you.

Check your PM please

GTX JOHN · 10-09-2020, 09:03 PM

Quote:

Originally Posted by Billy Nees

Yeah, I wish that this were true John but look at all of the replacement Holleys that have "down-leg" boosters. The only thing that matters anymore is throttle bore and venturi size.

Really?

Glad I still have a lathe and my moto tools

Does fuel inlet position still matter?

I think we are going to find a tenth!

Billy Nees · 10-10-2020, 07:32 AM

Quote:

Originally Posted by GTX JOHN

Does fuel inlet position still matter?

Not since they let the Edelbrock Q-Jets in.

Mark Yacavone · 10-10-2020, 12:52 PM

Quote:

Originally Posted by Billy Nees

If you are still running the 307 roller combo, you must use an 800 CFM Q-Jet. Plus .005 or minus .015. Same carb that I have to use on my 301 Pontiac.
Just a bit of advice, don't listen to what some "previously employed by NHRA" people might have told you.

I did not know that. I know several guys who used a 207 carb in place of an 800 late model
I assumed the rule was kinda like .030 over, vs. .080 over.

How's that "no tech" working out, again?

GTX JOHN · 10-10-2020, 04:25 PM

Quote:

Originally Posted by Billy Nees

Not since they let the Edelbrock Q-Jets in.

Thanks .....The price just doubled on all mine =
Better than the Stock Market!

10-09-2020, 02:03 PM	#1
Jeff Stout VIP Member Join Date: Dec 2001 Location: phoenix Posts: 1,484 Likes: 65 Liked 704 Times in 281 Posts	Carb size ? A max size carb per rules for each motor combo. I know we no longer need carb numbers to be correct per engine. Any rule on how small a Qjet you can have? Asking to try a small cfm if legal.

10-09-2020, 05:15 PM	#2
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,719 Likes: 2,767 Liked 2,425 Times in 687 Posts	Re: Carb size ? Carbs still need to be the original Specs/Dimensions including boosters/Throttle blades. have I prefer the Edelbrock Replacement Q Jets. I have several in great shape and even NOS.! I believe a 750 must replace a 750 and 800 replace a 800. You can easily look down the throat to see the difference. Believe it or not = I used to race a National Recording Holding 86 Ram 100 with a Q jet. __________________ John Irving 741 Stock 741 Super Stock Last edited by GTX JOHN; 10-09-2020 at 08:58 PM.

10-09-2020, 05:49 PM	#5
Jeff Stout VIP Member Join Date: Dec 2001 Location: phoenix Posts: 1,484 Likes: 65 Liked 704 Times in 281 Posts	Re: Carb size ? Thanks for the response. Saves my testing that idea.