u want a t-5, pull it out of a 87-93 mustang 5.0, use the same bell housing off of it. ull find some at ur local junk yards, u can stick that on ur current 289, and have it converted to stick mean while u look for the 351w. then later u can just drop in the 351w. ull have more fun when u get ur t5 any way vs gettin a 351w on a c4, u just get threw the 3 gears faster, where as the t5 lets u build more speed, and itll make it more fuel efficient, and u can choose how high u wanna rev all that fun stuff.
ur gonna need the clutch pedal, and all the linkage as well plus the equalizer/z bar, or a hydraulic clutch kit, flywheel and pressure plate to mount to that, a after market cross member for the tranni, a special tranni mount. ur c4 yoke will work on it, mine did, but i didnt use it. u might or might not have to shorten ur drive shaft. lot of ppl say u have to, but mine didnt need it they recommend 1" to 1 1/2" of play from yoke end to tranni tail, (after i had about 400 pounds on the trunk, 3/4 inch of play was good enough for me)
u can even use the 5.0 out of the 87-93 mustang u get the t-5 out of, just put the 289, oil pan, dipstick, timing cover, i doubt the fuel pump will work on it seein how theyre efi 302s and dont have the fuel pump drive, so u get an electronic fuel pump, bolt on an intake and carb, and u get to benefit from a roller valve train, and some extra hp. just an option, if finding a 351w is to hard.
65 ht (c code) 351c, t-5, 8" daily driver
87 fox lx 5.0, t-5, 8.8, pops car now
65 fb (c code) under construction