I have a 2004 Duramax with the 5 speed Alison. I was wondering if anyone knew that a 3 inch downpipe was the biggest you could fit between the firewall and the back of the motor? I seem to have too small of a down pipe and was wondering if I could upgrade.
No matter what the conditions are if I'm on 5 on my chip and put the skinny pedal to the wood
the EGT's will jump up to 1418 between 3rd and 4th (that seems to be when it lugs the most).