The 351W heads are almost a direct bolt-on except for hardened washers for the 1/2" bolt holes instead of 7/16" on the 302 heads. Try to find the small chamber 69-70 heads which are 60cc, otherwise you'll lose compression. Those heads have 1.84/1.54 valves which are bigger than the 1.78's on the 302 heads. Better flow. You can use your intake. 351C are Almost impossible and not feasible to put on .
Better breathing, especially the earlier 351W heads, which also reduce the compression ratio less than the later ones.
For your application, the 351W heads are better...installation details have alread been covered. I would suggest an aftermarket intake as the 302 intake is pretty restrictive (lower), but it still will work in the interim.