The early V-8 Mustangs (Fox Body) were from1979-1993 they went from little front brakes and drums and carbs to 1987 bigger brakes and FI. Just a bit about drums and Mustangs. Our ITB Mustang is a rear drum car and we just ran the 13 hour VIR race and had no problems with the drums. Granted we crossed the scales at 2650 but I don't see drums as a problem.
Another thing about spec lines, our car is speced from 1979 to 1993. There are so many differences betwwn the years it would make your head spin.

Put the 79 to 93 cars on a seperate spec line and I might give it a try.