Dont do it man, i work on the new f-bodies....yes it is true that you can get gobs of Horse out of these LS motors with what seems to be "easy" mods. But just to name a few things here:
An LS1 Hot Cam is the cam of choice.....the cam alone is around $400

The LS1 have extremely weak and cheap oil pumps....i guess GM figured they could save a few bucks there. Around 60K miles they fail for no reason.

Do you really want a computer on your car?....think about the head aches you get from your desktop at home....now multiply that by 100 and shove it under your hood.

For the money you are ganna spend on that LS1 or LS6, or the new Ls2 you could have a pretty stout 383 that will get you around 12-19 mpg....i get 10mpg in my stroked BBC, most people get sick when they here that, but i am more than happy with that. She has done the Hot Rod Pwer train 2 years in a row and only went through a water pump.

There is a kit made to swap an LT1 or LS1 into a first gen, and it seems pretty murphy proof, but i wouldnt spend the money for the motor....just not worth it for what you get out of teh box.....now if you score one from a totalled Camaro or Fireturd make sure you strip out the wiring harness