Ok guys, had it on the dyno this afternoon.
I'm happy so far with the results.
I changed the spring out with a 7lb spring. Dyno and gauge is showing 7psi.
Intake temps were at 82 degs with it being 89degs outside. So the intercooler is doing it's job, with a little help from some water injection.
Test vehicle is an '05 Avalanche with a stock 6L, small 212 cam.
Muffler is a magnaflow.
Truck does have 32" heave 20's, I'll be dyno'n it with stock wheels later today. I'm guessing another 30hp just from stock wheels.
HP: 498hp
TQ: 489tq
at 7psi.
Time to start cranking it up.