a Newbie forum question sparked my curiosity about this - I upgraded my original '72 350 2bbl single exhaust to a 4bbl dual when building it up but kept the factory manifolds. Are there any noticeably functional/performance differences between original 2v and 4v manifolds that would make them worth a swap?


I'm running dual 2.25" exhaust now.


If so, are earlier year versions better than later and any physical fitment differences between them - i.e. would I have to modify my exhaust pipes to fit?

 

The small block Olds exhaust manifolds are pretty much the same from 1964-1985. 2bbl, 4bbl, single exhaust, dual exhaust, W-31, it doesn't matter. They are all the same. Factory dual exhaust cars got a cap on the second port on the passenger side manifold.