340 exhuast manifolds

[oldjunk]

Are there any differences in performance between the 70, 71 or 72 stock exhaust manifolds?

 

[fishy68]

Yes. I can't remember if 71 was still the good/old style or if that was the year they changed but I know for sure 72 and 73 is the same manifold as you'll find on a 360 2 barrel engine. I saw a dyno report a few yrs. ago that compared them and there wasn't a big diff. in performance but the older ones were better. Approx. 10 hp diff. on a 300 hp crate engine if I remember right.

 

[breakstuff]

What size is the outlet on the 72/73 manifolds? Or shoud I say what size pipe will be fitting up to it?

 

[fishy68]

What size is the outlet on the 72/73 manifolds? Or shoud I say what size pipe will be fitting up to it?

I think it's 2" but I'm not positive.