Flow numbers for Stock LS1 Heads
Lift Intake Exhaust
.100 66 51
.200 140 94
.300 193 126
.400 210 150
.500 219 162
.550 223 167
Notice that the intake flow is very good up to about .300-.350" lift and stalls above .400" lift. I believe the swirl vane and short turn radius are causing this problem. This indicates that the stock valve job is pretty good and a higher lift cam (Over .500" lift)will have minimal effect unless accompanied by longer duration. In my opinion, this is not good peak flow for a 200cc intake port. I will perform some simple mods to the port, removing a minimal amount of material, and post the results Let's see what happens!
Paul J.


