Rebel Rouser

No offense taken good Sir! I’m just glad GM is even going in that direction. You are correct, the stock numbers on the 8.1 are pathetic in terms of hp to cubic inches. Raylar fixes that problem, but my kids still have to go to college so I don’t have a 529 Roth for the big block yet ?? But, turning the TM off and running a premium tune after you open them up and let them breathe, and the 8.1 reminds you what unbridled instant torque felt like in the late ‘60s/early ‘70s. Puts a smile on my face every time I drive it. I hope the 6.6 does for you and that’s all that matters.

All true and good points. Can’t wait for diablo or edge or HP, anybody that will make a tune for these new beasts!

Well as the proud owner of one of those “vaunted 8.1”s with the Allison, I’m a little partial! ? But I test drove a new crew cab High Country. I was impressed with the size, the weight, the cab, the tech, and to an extent, the ride. I was not impressed, however, with the power band on the truck. From a dead stop, my big block will absolutely ROAST my 35” A/Ts and chirp out of 2nd gear. Granted, I have 4.10s, intake, headers, custom true dual exhaust and a canned tune, but I did expect more from the advertised numbers from the 6.6. I floored it coming out of the dealership expecting it to pin my eyes back like the 496 does.... not so much. Higher in the RPM band, it really picked up and THEN it was impressive. So I looked up the torque curves for each engine and confirmed my suspicions. The torque curve on the 8.1 is incredibly flat comparatively. And the 8.1 starts off from idle with 400 ft lbs. The 6.6 on the other hand, starts around 350 ft lbs from idle but climbs. However, the 8.1 reaches peak torque at 3200 RPM whereas the 6.6 is a little later at 4000 RPM. The big difference other than off the line is the horsepower. Over 4000, the 8.1 falls on its face thanks to a terrible intake design. The new 6.6 is a BEAST over 4000 RPM. I think when tuning companies come out with software for this new 6.6 motor, it will be unstoppable!

And the verdict is???

Hey y’all, not new but been gone a long time. Other forum I was on is dying. Got a 2005 Silverado 2500HD Crew 4x4 LT2 with 8.1 and 5 speed Allison. Bout 165k on the clock. Tons of extras. I see the small block forum in here, is there a dedicated big block forum too?