my truck is a four speed

 

i dont see how yours is a RCSB an went slower than mine. are you stalling at the line?
my truck will stall to about 1700...an not spin off the line.

 

no not stalling cause if i do it does spin more.

 

i think maybe your long tubes helped you out. i have full exhaust plus the 09 comes with 3 cats.

 

....i went 15.6 an skipperdaddy keeps up with me well..he has the same truck just 6L80E in his with a CAI (i didnt have a CAI yet) its a lil hard to believe the SC is being outran by a CC..when i run on my 20s and stall i dont spin off the line.

 

The 17's he is running on the rear makes a big difference. I will be taking my 20's off this weekend when I go to the track. And putting on some smaller wheels.

 

my 17s are the 265/70/17s same tire height as the 20s
ill compare the 17" vs the 20" theres not gonna be a difference imo

 

who's your tuner? whats your shift points? how firm is the shifts?
if tuned with EFI/HPtuners was it street tuned or cookie cutter tune(same tune he puts for everyone else) or a handheld programmer(if so i recommend selling that and getting a custom tune)

 

oh 1st i thought you are running 20s all around there would be a great improvement on my time if i go that route.

my tune is by someone local here and is very good. and its a street tune.

 

im sorry but the 20s in the rear vs the 17s in the rear is no difference imo, if you wanna do weight and tire height an air volume blah blah blah. its the same weight if not then very close and wont make a difference.
how about this i put the bald 20s back, and put the 87mm, stock air intake back on and prove that itll be the same 15.6x all day long