A 318 is only 22 cubes less than our famous & beloved 340. 318 blocks are not as strong as 340 or 360 blocks. However they are plenty strong for a good street motor. 350 hp is easy. 400 is do-able. As for 360 heads lowering the compression ration due to their larger chamber. Well thats not a bad thing "if" you want to run the cheap 87 octang gas. Stroker motors are the cheapest way to get good HP #'s, but are not too good on gas. I have a stock 318 short block in my bracket car. Orginal pistons still in it. 360LA heads 340 cam and its was cheap to build. A friend of mine has a 2002 Z28 Camaro 350. She says is stock (not so sure as I look at the cold air box on it) and was rated at 350HP. I have no trouble beater her in a heads up race. Her car is a bit heaiver & has a highway gear so she is gaining at the top end, but my 4:10 gear is holding me back on the top yet I still get by over a car length. Trust me that 318 of his can be made to run real nice. I would put headers on it though. Just my