Go 5.3L its alot cheaper. Or if you have the money go w/ a TRT 6.0L 402 & STS custom kit. So far are 402 made 640hp at 6psi. I think that would have the burb moving pretty good.
Or just get a TRT 5.3L w/ forged pistons, ls6 cam and make 650hp at 14psi.

I bought my 5.3L, 4l60e and wiring for like $500. You can find good deals on 5.3l.

Buy the wiring harnes from Allen! It will save you a ton of time and looks bad ass!