I am going to do the exhaust on my 80 F150 w/a 351M and I would like to know if it requires a catalytic converter or not? I am hoping not but the original motor in my truck was a 302 and it was catalyst so I don't know???

 

yes.

I know in PA, you are not allowed to swap in an older motor into a new vehicle. I don't know if you got your from an 80-82 f-250HD or not.

but, yes, it should have a cat and air pumps.