I have a 78 F100 with a 460/C6 setup. The guy that my dad bought it from built it for bracket racing so you can only use 93 gas and get less than 10 mpg. I have a friend with a really nice 302/C4 from the 70s. I don't know what it originally came in.

My question is what obstacles will I be facing in this swap? I'm mostly concerned with the driveshaft and whether it will work. What other problems are there?

Thanks for your help!

 

The 460 is fun. I'd keep it. I have one in my 77 shortbed.

If the truck had the 460 from factory, or a 302 351w from factory, then the 302 will bolt in with stock 78 truck motor mounts. A trans crossmember in the truck now may be able to be moved so it will work. It only bolts in so a few more holes and you're done. The c4 came in some of these trucks but they were the "heavy duty" sorta, pan fill trans. Don't worry if its from a car. The crossmember and trans mount are virtually in the same place.
If the truck had a 351m and the 460 is using swap mounts, then you'll need to locate a set of 302/351w frame mounts.

Driveshaft is different. The c6 is longer and uses a different slip yolk.