You got me confused. You said" Then you start talking about heads and stuff. Then suddenly you are into pistons and boring. And then, And then And finally, Yur all over the place, like a fly on a sugar-high! Slow down, you're giving me the Heebe-Jeebies,lol. My suggestion is to just get a 360 and be done with it. But if you just have to have a 318, My recommendation is this; Make it high compression; I mean really lots of cylinder pressure,like 185psi, and put a short-period, Hi-lift, solid lifter camshaft into her, and then let her buck. That will take alloy heads. You will need a big Holley-type carb, a hi capacity oilpan, a high powered ignition, and a good tuner. A Commando 4-speed would help keep it on the pipe; but a hi-stall will launch better. If you want a cheap, big-fun, all-round GREAT street combo, you can copy my 360 recipe. Coming from a 318, you will never look back.