Reading through Super Chevy mag (or one of those GM performance mags) at lunch time and read an article about the build up of an LSX motor for Reggie Jacksons Camaro. 454 cubic inch Iron LSX bottom end with LS7 heads on it and a 4 barrel manifold similar to my Victor Jr but with a carb on it. This monster made 640HP and 611 foot pounds of torque using a pump fuel friendly 11:1 comp.
The LSX block is an Iron version of the gen4 LS7 block and is interchangable with the LS1, LS2, L76 etc. It can be safely bored to 4.250" and has been designed with input from pro stock legent Warren Johnson. Supposedly it's good for 2500HP!
The great thing about this block is that it costs a fraction of the alloy LS7 block with loads of performance potential. And it's got room enough to build 500 cubes.
Here's some details on Reggies Camaro
Cheers