The 302 heads actually flow worse than the old open chamber 318 heads or any other 318 head actually. They do have more swirl and closed chambers for a little more compression but the flow will probably make more power in the end so you need to do some upgrades in the flow department or you will not be happy. The magnum heads are better flow, swirl and compression and can easily be disquised, the original valve covers still bolt on, the ex manifolds bolt on and you can redrill the intake bolt holes to keep your original intake. The 1.6 rockers will make it seem as though your cam is bigger to boot. If you just have to run the 302 head put in 360 valves and touch up the ports, bowls and PR pinch a little and run the 360 2bbl cam fast mentioned, grind down the sharp point in the middle of the chamber and unless you run a steel shim head gasket you will lose any compression you gain from the smaller chambers and then some. The only place I can find steel shim headgaskets is in the MrGasket MLS head gasket, I buy one gasket pop the rivets out and the two outer layers become two individual steel shim head gaskets.