2009 gmc sierra 1500 5.3 LH6 with 6l80e 6 speed transmissions 4wd

specs:
AIRAID cold air intake
OBX long tube headers+ catless Y pipe
custom 3" exhaust with single 3" cutout ,magnaflow 13762 xl muffler
3" tail pipes
8mm taylor wires
NGK iztr5b11 spark plugs

dyno tuned on 95 octane saudi gas ( 93 american)

run was in 4th gear unlocked
https://www.performancetrucks.net/forums/gFCADuUgCAA befor tune



with cutout closed



with cutout open



with cutout closed
24+ whp
54+ tq

 

sounds about right. Nice job. Now throw a cam at it!

 

cutout results are identical to what I saw on my non-cammed setup. It added 3 rwhp.

 

Mine added 10 on a mustang dyno.. but i'm just cool like that

 

the dyno says 3 but the street says more

i realy feel the difference and iv raced my cousin twice with it closed and agine twice with it open and it did gave me alot more than 3 hp

i think that wasnt on the peak hp

 

another thread has similar mods to your but a 6.2, its a good comparison. 6.2 out down 360ish i think.