Have you already got a 351 engine, or are you gonna be swapping parts from yur 302 to the 351w. Some engine parts from a 302 will swap and some wont, heads will interchange, oil pan will not do to it being wider. You will need 351 swap headers, also the intake will be different. you also might have problems with hood clearance, they make drop motor mounts, that drops the engine about .75", they say these might cause clearance issues with stock k-members, so you might be better of to get a cowl hood of some sort. I beleive you also have to have a different damper, 28 ounces instead of the 50 that the 5.0 uses, i think.... You will also need a crank pulley spacer to properly align your belts. But if you already have a built 351w then alot of the stuff is not needed.... Im in the process of building my 408w stroker, so i been doing alot of research also.
-AJ