Just have an exhaust shop fab you up a dual 2 1/4" exhaust using any performance muffler or mufflers you like.
If you want it to look original, you'll want two pipes running down the passenger side of the car, with a dual-in/dual-out muffler.
Other options are:
Two pipes down one side with a dual in/single out (go 2.5" or 3" out if you do that).
Two pipes into one at the stock location, then a single pipe and muffler out (not a bad way to go, go 2" or 2.25" down, then 2.5 or 3" out).
Two pipes into mufflers that dump at the rear or turn out in front of the rear wheels (local laws will dictate that one)
Sidepipes (Ever see an old AC Cobra or 60s Vette?)
Whatever you do though, don't go back with the stock sizes... just an exhaust system alone will make a noticeable difference in the way a 302 powered II drives, throw a 4-bbl carb, intake, headers, and exhaust on one and take a fox-body owner for a ride and they'll damn near convert to our weird little Pinto-based-econo-car-worshipping religion.
Since I don't have the car just the engine I was just wondering what the stock pipe size was so that when I start my performance upgrades I have a baseline. I am considering long tube headers into a true dual no catalitic converted and eventually dropping the motor into a '68 Mustang coupe and running the pipes out the sides with Cherry Bomb glass packs on it, old school style.
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, builds, modifications, reviews, engine swaps, classifieds, troubleshooting, maintenance, and more!