I have a carbed 351 W in my '58 f100. It fits well but headers is an issue on account of the protruding steering box. If you are planning on using stock manifolds i would say that you should have clearance all around. If you go with headers you will need block huggers.

Also plan on making motor mounts with either motor. The 302 is wider than the 289 and the 351 W is wider than the 302. So either way you go you will probably need to make some mounts. It's no big deal though if you have a grinder with a cut off wheel and a welder. I made mine out of 4" c-channel and it fit the motor mounts like a glove.

One other thing to prepare for. You will need an electric fan for the radiator. That is the setup I have and it works fine. You can get one from JEGS or Summit Racing for less than $100. A regular fan wouldn't fit. It would be touching the radiator. At least it doesn't look like it would to me. I never tried it. On mine there is probably 1/2" between the water pump pulley and the back of the electric fan.

I know nothing about putting EFI into a non EFI vehicle. Though I have read about it before and it seems as though as long as you have the engine harness and the computer for that engine it is very doable. Granted you have enough patience to not only re-wire from the cab forward but also do something complicated without instructions.

Good luck. I look forward to seeing how it turns out.