im looking at putting a mild cam and roller lifters on my 5.3 i have also heard that i could put the heads off a 6.0 and onto my motor. i was just currious to see if anyone knew of someone thats done this, or has something similar done to there truck. i had a mechanic tell me i could see around 100 additional horse power when done.

 

If you put the 6.0 heads on you will drop your compression ratio (CR) as the chambers are 71cc vs 61.15 on the 5.3 heads. Not a good move unless you plan on adding a turbo or supercharger.
See here: http://www.smokemup.com/tech/ls1.php
Here is a link for 100hp gain
http://www.ls1truck.com/forums/front...in-budget.html