A 302 is light, inexpensive, and a very good little motor. A 351 W is light, harder to find, and is also a good motor. Both respond well to light modifications, such as a lumpier cam, better valve springs, a hot ignition, and a better exhaust. The 351 will pull like gangbusters through the mid range with a 260 adv, cam. A 302 just pulls a bit better. Transmissions and rear axle gears play in to the total package. Playing with these costs money, how hard do you want to play? I can say how I want mine, but we may not have the same thing in mind for the end game.