Exhaust/muffler

[paul86]

what should I replace my stock 86 305 with....Flowmaster 70 or Magnaflow?
Want to change from fron to back with new pipes/cat and muffler...no more than $500 though!
It need to open up and have more power (yeah I know it's a 305)

 

[gravdigr]

Actually it has been my experience that the 305 doesn't need much breathing. The PO of my '86 had duals with flowmaster 40s. I had to remove then and go with single exhaust for emissions. I put on a thrush turbo muffler and cat with 2 1/4" pipe and actually gained power, especially on the low end. Don't ask me why.

 

[wubba_65]

Smaller engine is slightly higher reving (makes power at higher RPM) and the back pressure helps it make more power. Similar to how smaller 4 cyl engines with a turbo need to have a matched exhaust (but 4 cyl much more vulnerable to wrong combination than a bigger NA engine).