ZachW04Stang

I ran 1 3/4 on a basic 302 but that only because 1 5/8 headers weren't big enough for my exhaust ports.

94StinkinLincoln

well i have a 331 that needs 1 3/4 longtubes with 3in all the way to the end for max performance...its no where close to stock like yours. now if you planned on making some good power down the road get the stuff now. i didnt so its going to cost me more in the long run. the only problem you will have is low rpm power, it will suffer. 3k plus it will roll lol

88BlueGT

+1 to what everyone said, go with 1 5/8 & a 2.5 col.

And BTW, ALL LONGTUBES are illegal. no way around it.