exhaust
Burning Brakes
Joined: Jan 2003
Posts: 755
Likes: 32
From: Roswell Georgia
Without knowing much more about your engine's timing events, the best I can recommend is maintain the same size pipe that fits over the collector's reducer all the way back to your mufflers. If you have a choice of reducers, pick one that has at least a 2 1/2" diameter outlet. Having a set of mufflers that will handle the exhaust airflow w/o causing excessive back pressure is a must for best power.
For some very good general header info that might help, check out this article by David Vizard from Stock Car Racing. Here's the follow-up article featuring Jere Stahl on headers.
Good Luck!
For some very good general header info that might help, check out this article by David Vizard from Stock Car Racing. Here's the follow-up article featuring Jere Stahl on headers.
Good Luck!
Last edited by mr.beachcomber; Mar 9, 2015 at 08:22 AM. Reason: Added outlet recommendation for reducer
Burning Brakes
Joined: Jan 2003
Posts: 755
Likes: 32
From: Roswell Georgia
Found this article today about exhaust systems on big cubic inch SBC's. According to the article, they recommend 1 7/8" headers for SBC's with displacements above 420 cu in. Definitely worth a read. 
