I was told that only one of the two are compatable with the stock 302 out of a 87-93 mustang and i see sum 351W heads for kinda cheap on ebay and i heard that using the 351 heads makes a huge difference so just curious do they both work or only one and if so which one would work on my 302?

 

A 302 and a 351w are basicly the same thing. 351's have a taller deck height causing them to be wider so things like the oil pan, acc brackets and the intake will be different. The heads will work but you need a set of bushings or step down head bolts to bring the 1/2 head bolt hole of the 351 head to the 7/16 head bolts a 302 use. 351 heads can make for better performance but you want to find a set of c9 or d0 heads (69/70) because of the smaller CC and bigger valves.