Carb number question

65hardtop · 11-18-2016, 05:30 PM

In stock, If I have a carb that does not have a number that is on the list of acceptable
carbs but has all the correct dimensions is that ok or not?

Thanks

bob3240 · 11-18-2016, 06:14 PM

Yes, NHRA stopped making us have the matching numbers years ago

Jim Caughlin · 11-18-2016, 07:21 PM

What? Your saying that if the bores and venturis are the correct size, it's legal??? Not in the part of the country that I race in.

Coleydog · 11-18-2016, 09:45 PM

Quote:

Originally Posted by Jim Caughlin

What? Your saying that if the bores and venturis are the correct size, it's legal??? Not in the part of the country that I race in.

Every AVS carb from 68-70 on the 340 and 383 have identical bores and Ventura size, I doubt those little numbers on the corner mean much now after 50 years.

jmantle · 11-18-2016, 10:59 PM

Quote:

Originally Posted by Jim Caughlin

What? Your saying that if the bores and venturis are the correct size, it's legal??? Not in the part of the country that I race in.

Jim, NHRA relaxed the rule several years ago. Still has to be the correct carb with the correct throttle bore and venture dimensions, numbers don't matter.

Jim Mantle

Jim Caughlin · 11-19-2016, 08:48 PM

I understand the part number part of this question but you better make sure that things are configured as original. I have seen these items get someone bounced (at least on Holley carbs):
Center pivot bowels that weren't OEM
Dual inlets that weren't OEM
Changing metering plates to metering blocks
Secondary idle circuits
Throwing away the vacuum secondary parts
Polishing bores (even though they measured legal)
Milling down the throttle rods
Secondary accelerator pumps that weren't OEM

There is a lot more to what constitutes a legal carb than just bore and venture.

If any carb that meets the measurements are legal, why does NHRA have a list of legal replacements, wouldn't any carb that measures correctly be legal?

I know my case is a little different (SS modified), there are specific carb numbers and minimal modifications that are allowed. Every time I have been torn down, the carb gets a very careful visual inspection beyond the obvious measurement check.

Jim Caughlin
SS6019

11-18-2016, 05:30 PM	#1
65hardtop Junior Member Join Date: Aug 2009 Posts: 18 Likes: 0 Liked 0 Times in 0 Posts	Carb number question In stock, If I have a carb that does not have a number that is on the list of acceptable carbs but has all the correct dimensions is that ok or not? Thanks

11-18-2016, 06:14 PM	#2
bob3240 Member Join Date: Jan 2009 Location: lebanon ohio Posts: 251 Likes: 3 Liked 16 Times in 5 Posts	Re: Carb number question Yes, NHRA stopped making us have the matching numbers years ago

11-18-2016, 07:21 PM	#3
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 679 Likes: 77 Liked 786 Times in 240 Posts	Re: Carb number question What? Your saying that if the bores and venturis are the correct size, it's legal??? Not in the part of the country that I race in.

11-19-2016, 08:48 PM	#6
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 679 Likes: 77 Liked 786 Times in 240 Posts	Re: Carb number question I understand the part number part of this question but you better make sure that things are configured as original. I have seen these items get someone bounced (at least on Holley carbs): Center pivot bowels that weren't OEM Dual inlets that weren't OEM Changing metering plates to metering blocks Secondary idle circuits Throwing away the vacuum secondary parts Polishing bores (even though they measured legal) Milling down the throttle rods Secondary accelerator pumps that weren't OEM There is a lot more to what constitutes a legal carb than just bore and venture. If any carb that meets the measurements are legal, why does NHRA have a list of legal replacements, wouldn't any carb that measures correctly be legal? I know my case is a little different (SS modified), there are specific carb numbers and minimal modifications that are allowed. Every time I have been torn down, the carb gets a very careful visual inspection beyond the obvious measurement check. Jim Caughlin SS6019