Originally Posted by Chris@HPS
HPS did a before and after dyno session to get the gains from our CNC Ported LS6 Heads. After the new HPS CNC Ported heads were installed with no other changes to the tune off the street the HPS CNC Ported LS6 Heads averaged a 30rwhp gain. We went to lunch, came back, I added 2 deg. of timing from 25deg. to 27deg. and added 2% of fuel as well. The gains were another 20rwhp. So all in all we gained 50rwhp and 30rwtq. This was on a 5.7ltr.motor with a mild camshaft 598-600lift-230 duration on a 114lsa,long tubes and a LS6 intake, K&N CAI.
All in all we are very pleased with the gains and the customer has already called and said that there is a very noticable feel in the torque improvement and power!
Some very nice improvement with this being the only diff.