The joy of a pre-86 mustang
I used to have the same issues with my 79. But if you look at it in a different way. Almost every single part made for a SB ford from the late 60's and up will fit your engine. The few things you have to watch for when buying parts are the headers, oil pan, motor mounts, and maybe a couple other small things. As i believe there are differences between pre-86 and 86+. Heads/cam/intake are great starting points for you. The early 80's 302's were pooches for the most part. Though you can squeak out sufficient power with the stock heads if you do a port and polish job. Cam and intake are fairly cheap.