What block are you using? How much boost are you planning to use? You don't need to go with low compression unless your running a lot of boost, and then you'll need a better block. I think if you stay in the 9's on compression, you'll be able to make more power and boost than the block will be able to take. I met a guy running 10.5:1 compression on 10psi boost on a 347 running 93 pump gas. Makes over 600hp!