Header sizes for a 3.2 ---> 3.4 conversion, beating it to death...
 

If you had a preference of a header primary size for 3.2 motor turned into a 3.4, would you run 1 5/8" or 1 3/4"? I don't want to choke off my higher rpm power, but it would be nice to pick up some low and mid range torque. Car is a street car that sees occasional DE use. SSI's are out, I'm convinced their tube dia is too small for the job.

Probably splitting hairs but worried about lack of backpressure, etc.

Thoughts?

BG

1 5/8ths unless you are turning 8500 rpm.

1 5/8 is what I am going to go with. I am planning on using the 993 heat exchangers as I want/need heat. Just about all the threads I have have looked at say 1 5/8 unless you have a really hot cam, then 1 3/4.