I am interesting in replacign the stock muffler with soemthing with lower back pressure. Can anybody reccomend which muffler has the lowest back pressure while still being quiet, also not break the bank.

 

...ain't real cheap. dynomax is probably the best known but there must be others...you don't any info about the car so, it's hard for someone with real experience with specific brands and applications to give you good advice. you might try calling several exhaust specialty shops to get an idea of various products and cost...keep also in mind that the muffler isn't the only thing in the exhaust system that can influence back pressure

 

It is a 1986 F150 302FI 3 speed with over drive.