Typical header dimensions

Bob F · 02-08-2021, 08:57 AM

What’s the typical header sizes used on an A stock bbc?
I run a 402 in my bracket ride and am using a hooker comp header with 2” tubes & a 3”1/2 collector.
Turns low 10’s at 130 plus

Billy Nees · 02-08-2021, 09:27 AM

Looks about right.

GTX JOHN · 02-09-2021, 03:56 AM

Sometimes 2 1/8 on our Max Wedges -I would think
maybe a bit bigger than 2" on Big Block GM.

However, I have not raced a big block Chev. since early 70's
so what the Heck would I know. Maybe a Step starting @ 2" and
going up?

Bob F · 02-09-2021, 01:05 PM

I’d been wondering if the collector is too big @ 3”1/2

Billy Nees · 02-09-2021, 03:31 PM

I would say no....

GTX JOHN · 02-09-2021, 11:08 PM

I agree with Billy.

L.Fite · 02-09-2021, 11:21 PM

Quote:

Originally Posted by GTX JOHN

Sometimes 2 1/8 on our Max Wedges -I would think
maybe a bit bigger than 2" on Big Block GM.

However, I have not raced a big block Chev. since early 70's
so what the Heck would I know. Maybe a Step starting @ 2" and
going up?

A "stock" BBC exhaust port is right at 1-7/8 in it's major dimension, maybe slightly more or less.
(Measured with a tape.)
So there's that...

Bob F · 02-10-2021, 07:32 AM

I’m hunting around to drop up a tenth or 2 that’s all.
Maybe grasping at straws during the winter boredom....

bert powell · 02-10-2021, 12:24 PM

My SS 402 likes 1 7/8" step to 3.25 throat merge collector for what it is worth.

Billy Nees · 02-10-2021, 12:33 PM

Quote:

Originally Posted by bert powell

My SS 402 likes 1 7/8" step to 3.25 throat merge collector for what it is worth.

And I'm guessing that it's an oval-port combo?

02-08-2021, 08:57 AM	#1
Bob F Junior Member Join Date: Sep 2007 Location: Bucks Co Pa Posts: 56 Likes: 16 Liked 14 Times in 10 Posts	Typical header dimensions What’s the typical header sizes used on an A stock bbc? I run a 402 in my bracket ride and am using a hooker comp header with 2” tubes & a 3”1/2 collector. Turns low 10’s at 130 plus

02-08-2021, 09:27 AM	#2
Billy Nees VIP Member Join Date: Oct 2002 Location: On a hilltop in Pa. Posts: 4,223 Likes: 3,103 Liked 6,791 Times in 1,524 Posts	Re: Typical header dimensions Looks about right. __________________ Billy Nees 1188 STK, SS World's greatest Under-Achiever!

02-09-2021, 03:56 AM	#3
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,530 Likes: 2,222 Liked 1,809 Times in 572 Posts	Re: Typical header dimensions Sometimes 2 1/8 on our Max Wedges -I would think maybe a bit bigger than 2" on Big Block GM. However, I have not raced a big block Chev. since early 70's so what the Heck would I know. Maybe a Step starting @ 2" and going up? __________________ John Irving 741 Stock 741 Super Stock

02-09-2021, 01:05 PM	#4
Bob F Junior Member Join Date: Sep 2007 Location: Bucks Co Pa Posts: 56 Likes: 16 Liked 14 Times in 10 Posts	Re: Typical header dimensions I’d been wondering if the collector is too big @ 3”1/2

02-09-2021, 03:31 PM	#5
Billy Nees VIP Member Join Date: Oct 2002 Location: On a hilltop in Pa. Posts: 4,223 Likes: 3,103 Liked 6,791 Times in 1,524 Posts	Re: Typical header dimensions I would say no.... __________________ Billy Nees 1188 STK, SS World's greatest Under-Achiever!

02-09-2021, 11:08 PM	#6
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,530 Likes: 2,222 Liked 1,809 Times in 572 Posts	Re: Typical header dimensions I agree with Billy. __________________ John Irving 741 Stock 741 Super Stock

02-10-2021, 07:32 AM	#8
Bob F Junior Member Join Date: Sep 2007 Location: Bucks Co Pa Posts: 56 Likes: 16 Liked 14 Times in 10 Posts	Re: Typical header dimensions I’m hunting around to drop up a tenth or 2 that’s all. Maybe grasping at straws during the winter boredom....

02-10-2021, 12:24 PM	#9
bert powell Member Join Date: Jul 2002 Posts: 241 Likes: 35 Liked 33 Times in 11 Posts	Re: Typical header dimensions My SS 402 likes 1 7/8" step to 3.25 throat merge collector for what it is worth.