I have a 91 vert with a 305 auto. Just installed headers (old slp) Y-pipe and Cat back with not cat. Also removed the A.I.R. system, I have a motor in the works that will take advantage of this this system, but for now I thought this would help the car, but it feels gutless now? Is this just to much of a free flowing exhaust for a 305 TBI system?

 

I remember there was a noticebly nice power increase when I swapped headers on the stock LO3 (including stock air cleaner).

Best is to check if everithing is set up correctly. Timing, ingnition, vacuum ports and hoses, header gaskets, pullys?, ...

 

what size pipes?

 

They are 1 5/8, headers with a four into one type y pipe then 3 in ch cat back, no cat, muffler has 2 2 1/2 tail pipes.

 

good size. did you remove the smog pulley? I'm trying to think what else that was involved in doing headers.