i have a 1991 f150 5.0 302 and im gonna change the exhaust. My old truck was a 1991 f250 with 351 put stacks on that one but when i did it i just ripped out the converter and it starting running crappy. On my new truck i wanted to put the exhaust on it but how do i bypass the catalytic converter?

 

Depending where you live, most muffler places won't do anything til the stock exhaust is past the converter. I think it's a big fine.

 

Well what you COULD! do, is get a High flow cat and dual exhaust, or whatever suits your preference. that way you still retain the "cat" but you also got the nice sound you've been looking for...just saying..

 

The presence or absence of a converter has no effect on the EFI system in these trucks, however if you remove the whole exhaust system including the y-pipe and converter you must re-install the O2 sensor somewhere close to the original location.