350sbcftw

do the 456 gears you will thank yourself later

reeperz28

iTrader: (1)

Stock converter flashes Mayby 2000 and foot brake's 1800 the new stall sounds like a good one with your converter and cam choice for towing. There's a YouTube video wondering around the difference on the dyno of mud terrain's vs little wheels with street tires and the number difference was crazy! 40 something rwhp gain with the little tires.

reeperz28

iTrader: (1)

YouTube - Broadcast Yourself.

HERE's THE VIDEO.. Good info if you like to see the difference.

1994Vmax

iTrader: (4)

The 6 liter and 4L80E convertors are nowhere near that tight in the trucks they came in. Those kind of numbers would be more accurate for a 4L60E transmission in a half ton. 2500 rpm flashing is very much the norm for a 6.0 liter with a 4L80E.

reeperz28

iTrader: (1)

If he'd gone any bigger with the stall would it take away a lot of mpg with towing heavy loads? This I have not experimented with just curious.

transamdave

iTrader: (1)

Did he end up having them milled?

TA2SLOW346

iTrader: (3)

Thats weird, my 06 ccsb z71 only flashes to 1500 rpms from a dead stop. Also my brother inlaws 04 3/4 hd flashes to 2000 rpms. Not sure whats the difference is, but ive never anything close to that.

jrmchevyman

Would not really lose much MPG it depends on setup and your tune, maybe 1 mpg loss in town since we are talking about small converters. A 2800 converter would have probably been perfect in his situation and he would still have full towing capabilities. Some guys go up to a 3000 converter with an upgraded tranny cooler and still tows heavy loads.

Another thing some converters have bigger / smaller diameters, different STR (stall torque ratios), efficiency etc and that also makes a factor in mpg loss.

In some cases your MPG can go up 1-2mpg because of Efficiency and torque multiplication.

Bama2door

My stock converter in my 6.0/4l80 2500hd ccsb flashes around 23-2400

1994Vmax

iTrader: (4)

I went out and played with my 1500HD driving out to one of the well pads. I can brake torque it to around 2200 rpm and then flash it around 2400 rpm or even a bit higher. Bone stock 1500HD that weighs in the neighborhood of 7500 lbs.

And the talk about STR is very important when talking convertors. An efficient 3000 convertor will drive just as nice as stock and still tow just fine. Or you can get a sloppy one that is just a pig to drive. 3000 would be great with that cam, and mpg is nothing great to start with in these trucks so a little worse is not that noticeable. Once locked however the stall speed doesn't matter making highway driving mileage virtually identical.