LS1 vs LS2

[Adrenaline]

Hello,
I came across this site while looking at turbo videos, and thought you might be able to help.
My 2 uncles always end up arguing over what motors are better (ford,dodge,chevy...you know the game) and they start spitting out stats about them. My question is what the difference between the two? I alos read on the the other posts that recomended a different block other than the GM block because he was going over 600 hp, is there a problem with the aluminum block when going over 600 hp? I dont know a whole lot about motors, just the basics. Hope you can help.

Thanks