305 header size ???

jmoneyfoot · 02-20-2020, 06:58 PM

My dish piston 305 2bbl made the most with 11/2"-15/8"step with a merge collector

Jim Caughlin · 02-20-2020, 07:28 PM

Based on past experience, assuming it is an auto trans, I'm thinking that 1 1/2 / 1 5/8 is going to work best with a 2 1/4 to 2 2/4 merged collector.

Tom Moock · 02-21-2020, 01:55 AM

Brian Fink, I thought you had Jack Davis small tube step headers on your car, per 2007 Hemmings Muscle Machines.

Brian Fink · 02-21-2020, 09:11 AM

The Jack Davis headers were 1 1/2 to 1 5/8 to 1 3/4 ;Stahl 1 5/8 were quicker . Jere recommended playing with extensions as opposed to a step design which I did .

Billy Nees · 02-21-2020, 09:26 AM

Jere wasn't a real fan of stepped headers. He also wasn't a fan of merged collectors. He said, "if your car picks up with a merged collector then your primary tube is too big".

Ed Wright · 02-21-2020, 05:19 PM

Quote:

Originally Posted by Billy Nees

Jere wasn't a real fan of stepped headers. He also wasn't a fan of merged collectors. He said, "if your car picks up with a merged collector then your primary tube is too big".

Yep!

James Jeschke Jr · 02-21-2020, 11:21 PM

1 1/2” x8”Lg. to 1 5/8”Lg. x8” to 1 3/4” is the best I have found.

02-20-2020, 06:58 PM	#1
jmoneyfoot Junior Member Join Date: Dec 2015 Location: waconia mn Posts: 92 Likes: 21 Liked 9 Times in 5 Posts	Re: 305 header size ??? My dish piston 305 2bbl made the most with 11/2"-15/8"step with a merge collector

02-20-2020, 07:28 PM	#2
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 685 Likes: 84 Liked 805 Times in 245 Posts	Re: 305 header size ??? Based on past experience, assuming it is an auto trans, I'm thinking that 1 1/2 / 1 5/8 is going to work best with a 2 1/4 to 2 2/4 merged collector.

02-21-2020, 01:55 AM	#3
Tom Moock Senior Member Join Date: May 2004 Posts: 801 Likes: 1 Liked 10 Times in 6 Posts	Re: 305 header size ??? Brian Fink, I thought you had Jack Davis small tube step headers on your car, per 2007 Hemmings Muscle Machines. __________________ Tom Moock 5704 STK

02-21-2020, 09:11 AM	#4
Brian Fink Member Join Date: Jul 2007 Posts: 173 Likes: 39 Liked 28 Times in 9 Posts	Re: 305 header size ??? The Jack Davis headers were 1 1/2 to 1 5/8 to 1 3/4 ;Stahl 1 5/8 were quicker . Jere recommended playing with extensions as opposed to a step design which I did .

02-21-2020, 09:26 AM	#5
Billy Nees VIP Member Join Date: Oct 2002 Location: On a hilltop in Pa. Posts: 4,506 Likes: 3,613 Liked 7,863 Times in 1,750 Posts	Re: 305 header size ??? Jere wasn't a real fan of stepped headers. He also wasn't a fan of merged collectors. He said, "if your car picks up with a merged collector then your primary tube is too big". __________________ Billy Nees 1188 STK, SS I'm not spending 100K to win 2K

02-21-2020, 11:21 PM	#7
James Jeschke Jr Junior Member Join Date: Jan 2013 Location: Pittsburgh Pa. Posts: 35 Likes: 20 Liked 19 Times in 10 Posts	Re: 305 header size ??? 1 1/2” x8”Lg. to 1 5/8”Lg. x8” to 1 3/4” is the best I have found. __________________ James Jeschke Jr. #1603 I/S