www.gmpartsdirect.com go to Performance Parts, Chevy V8 Small Block or Small Block Cams, and go down the list and look for the complete LT1-LT4 Conversion Kit. Comes with heads, intake, cam, roller rockers, studs, and all that jazz you need to install it. Some people on here dont like the LT4 kit, theirs ways around it. Other way is to go on
www.gmpartsdirect.com and go to upgrades, click on camaro ss, and on the list of engine mods has the complete lt1-lt4 conversion.
Ive read stock ported LT1 heads, can outflow stock LT4 heads. Personally Id go for a LT4 Hot Cam, or Comp Cams CC302-305 (emmisions legal) with ported heads & intake.