header tube size

Dave1695 · 11-17-2011, 06:22 PM

Small block Chevy stocker engine, is there any advantage to using a1 3/4 to 17/8 inch step header over the smaller 1 5/8 to 1 3/4 inch step?

Jim Kaekel · 11-17-2011, 06:25 PM

Probably going to need more information. Displacement? Carbureted or EFI? Compression ratio? RPM range? Car type & weight, etc., etc., etc.,

Alan Roehrich · 11-17-2011, 07:06 PM

That would be a question for PipeMax software, Jere Stahl, or Calvin Elston (who will tell you that you need 4-2-1 or tri-y headers). I'd need a detailed sheet on the engine to give you a good idea what it wants.

Dave1695 · 11-18-2011, 01:24 PM

The engine is .040 over 350, 10.5 comp. 750 dbl pump on victor jr, car weight 3100. running in IHRA Crate Motor class. Trap RPM 7200. I have always thought the pipe at head should be approx. the same size as exhaust valve but have gotten some opinions that the larger 1 3/4 inch pipe at head works better. The 4-2-1 collector is pricey but have heard well worth the investment. Thanks for your input gentleman.

Greg Hill · 11-18-2011, 05:18 PM

That motor is comparable to the motor in my car and my stahl headers are1 3/4 to 1 7/8 with a 3" collector. With a tri Y it's a whole different deal.

greg fulk · 11-19-2011, 03:09 AM

Dave I have had the 4-2-1 collectors & Merge both on my car......Same E.T. out of both. I would go with the 1 5/8 step to 1 3/4........unless your running the Fast Burn heads.

Bob Bender · 11-19-2011, 12:38 PM

1 5/8...............

Myron Piatek · 11-19-2011, 01:21 PM

Several IHRA and NHRA 360 Stockers, including myself, use off the shelf TTI 1 5/8"-1 3/4" step headers with good results. But they only manufacture Mopar applications.

K Stubbs · 11-19-2011, 08:48 PM

Whatever Greg Hill is running.

Wade_Owens · 11-20-2011, 12:48 PM

Either size will work well on a 350. Don't fall into the "equal length" trap. Just buy a merge collector from Performance Welding. The larger header may want to be shorter on the primaries. If you don't buy a merge collector, consider buying or building a header that fires in rotation into the old style collector. But, the bottom line is, it's all theory until you get an ET slip........

Wade O

11-17-2011, 06:22 PM	#1
Dave1695 Member Join Date: May 2009 Posts: 160 Likes: 0 Liked 15 Times in 11 Posts	header tube size Small block Chevy stocker engine, is there any advantage to using a1 3/4 to 17/8 inch step header over the smaller 1 5/8 to 1 3/4 inch step?

11-17-2011, 06:25 PM	#2
Jim Kaekel VIP Member Join Date: Jul 2002 Location: Michigan Posts: 1,227 Likes: 133 Liked 531 Times in 108 Posts	Re: header tube size Probably going to need more information. Displacement? Carbureted or EFI? Compression ratio? RPM range? Car type & weight, etc., etc., etc., __________________ Jim Kaekel 3836 STK

11-17-2011, 07:06 PM	#3
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,111 Likes: 1,570 Liked 1,814 Times in 413 Posts	Re: header tube size That would be a question for PipeMax software, Jere Stahl, or Calvin Elston (who will tell you that you need 4-2-1 or tri-y headers). I'd need a detailed sheet on the engine to give you a good idea what it wants. __________________ Alan Roehrich 212A G/S

11-18-2011, 01:24 PM	#4
Dave1695 Member Join Date: May 2009 Posts: 160 Likes: 0 Liked 15 Times in 11 Posts	Re: header tube size The engine is .040 over 350, 10.5 comp. 750 dbl pump on victor jr, car weight 3100. running in IHRA Crate Motor class. Trap RPM 7200. I have always thought the pipe at head should be approx. the same size as exhaust valve but have gotten some opinions that the larger 1 3/4 inch pipe at head works better. The 4-2-1 collector is pricey but have heard well worth the investment. Thanks for your input gentleman.

11-18-2011, 05:18 PM	#5
Greg Hill VIP Member Join Date: May 2006 Location: Louisville , KY Posts: 1,995 Likes: 68 Liked 279 Times in 68 Posts	Re: header tube size That motor is comparable to the motor in my car and my stahl headers are1 3/4 to 1 7/8 with a 3" collector. With a tri Y it's a whole different deal. __________________ Greg Hill 4171 STK

11-19-2011, 03:09 AM	#6
greg fulk VIP Member Join Date: Jan 2003 Location: jackson Posts: 1,165 Likes: 0 Liked 5 Times in 3 Posts	Re: header tube size Dave I have had the 4-2-1 collectors & Merge both on my car......Same E.T. out of both. I would go with the 1 5/8 step to 1 3/4........unless your running the Fast Burn heads. __________________ Greg Fulk 308 308X P/SA "ALL AMERICAN"

11-19-2011, 12:38 PM	#7
Bob Bender VIP Member Join Date: Jan 2009 Location: Maryland Posts: 1,733 Likes: 1,599 Liked 459 Times in 90 Posts	Re: header tube size 1 5/8............... __________________ Bob Bender 144 O/SA 2010-2012 National Record Holder

11-19-2011, 01:21 PM	#8
Myron Piatek VIP Member Join Date: Nov 2001 Location: Florida Posts: 1,542 Likes: 34 Liked 138 Times in 51 Posts	Re: header tube size Several IHRA and NHRA 360 Stockers, including myself, use off the shelf TTI 1 5/8"-1 3/4" step headers with good results. But they only manufacture Mopar applications. Last edited by Myron Piatek; 11-19-2011 at 01:24 PM.

11-19-2011, 08:48 PM	#9
K Stubbs Member Join Date: Aug 2008 Location: Benton, Arkansas Posts: 402 Likes: 0 Liked 20 Times in 3 Posts	Re: header tube size Whatever Greg Hill is running.

11-20-2011, 12:48 PM	#10
Wade_Owens Senior Member Join Date: Jul 2007 Posts: 578 Likes: 0 Liked 3 Times in 1 Post	Re: header tube size Either size will work well on a 350. Don't fall into the "equal length" trap. Just buy a merge collector from Performance Welding. The larger header may want to be shorter on the primaries. If you don't buy a merge collector, consider buying or building a header that fires in rotation into the old style collector. But, the bottom line is, it's all theory until you get an ET slip........ Wade O