If you want a driver or an Affordable shop truck and have a lowish budget I don't see any problem with 302. Big block = thirst. mate of mine had a big Galaxie convertible w/ 289 2bbl & duals +C4 that was a blast on the freeway or back road and was thrifty as hell. We also had a '66 F100 w/ a $150 289 that was a good old heavy duty workhorse. But not fast.
keep the 352. I just picked up a 66 f100 with a 352 and the only thing done to it is a 600 cfm edelbrock. It scoots pretty good too, and alot of "experts" dont know anything about FE's. Truck runs great, got 12 MPG, and made its first trip from south carolina to north carolina without a problem. Gas wise, screw it, if we were worried about fuel we would all drive a gay *** prius