ok, my existing exhaust all the way back is 2" od. now what size, header reducer, do i need to run it either inside or (i prefer ) over my 2" pipe?

 

Are you sure? The stock TBI exhaust is 2 1/4" outside diameter.

You want a reducer from your headers to your exhaust? What size are your headers?

 

well, it might be that is what previous owner threw on it-the 2 " i mean. after taking a better look he put wrong headers on it,and i can see where he ground the header flange off (where they bolt to the collector) off, to make them fit down through the frame and motor.and welded the pipes directly into the header. so now i don't know what to do?

 

Honestly, remove the old setup and install a new setup. Something like the Hooker 2055's 1 5/8" headers and y-pipe, to a Magnaflow 3" cat, to any 3" catback exhaust and muffler.

 

The 305 was choked enough stock--but smaller! Good grief.

JamesC