I have a 72 F100 it came with a 302 and have the option to get a 351 but no tranny.. Mounts arent a problem can get them almost anywhere here but not so sure bout the bolt pattern and tranny input shaft compatibility. So now I am one down one to go. since you answered my ? about the bolt pattern.
I'm going to assume you have a standard trans in the truck behind the 302. I know automatics were/are the same if the flywheel is balanced for the engine. Standards hmm. Time to get out your micrometer and measure the input shaft bearing on the 302 and the one on the 351. I'd assume the clutch plate should match,but you could remove it and slide it on the input shaft, compare the 302's and the 351's before installing. If the clutch on the 351 isn't correct I would assume you could find the correct at an auto part store, as Ford used both trannys behind both engines and visa versa. good luck in your swap. Dan