I have a pair of mid 80s 351 heads. Can they be used on 302s? No I didn't bother to even start to look it up myself. I wouldn't pay $300 for those rusty heads that still need to be cleaned and checked unless they were Shelby Maverick Boss 302 hemi heads.
Same heads used on both. Only difference is the size of the head bolt holes. 351's used 1/2" bolts vs 7/16 for the 302. You can buy shoulder washers from several vendors to use 351 heads on a 302. The same washers used for aftermarket aluminum heads.