silver-mod-o

iTrader: (15)

The first gear ratio difference in the 60 vs the 80 is a non-issue once you put a blower in the mix. All you'll do by overshooting the gear is hurt yourself on the top end since the OD of the 80 is lower than the 60. I agree, 4.10's would be great. But 4.56's would likely be more than most are comfortable with unless you're running some pretty tall tires.

You'll basically lose 10mph at 2000RPM with a 60E and 4.10's vs an 80E with 4.56's.

In the calculator below, use a 4.10 gear and .70 trans ratio, a 30" tire and engine speed of say 2000RPM (can be whatever you choose really as long as it and tire size stay constant).... Then change the ratio to 4.56 and the trans to .75 and check the difference. It's quite a bit.

http://spicerparts.com/calculators/t...rpm-calculator

motohead911

iTrader: (1)

I was in the same situation as you but I had a Silverado instead. I went with the 6l80 swap from a 4l60 and it was night and day different. I was able maintain 55 over both Cajon Pass and Mountain Pass on the 15 coming home from Vegas with an about 8000 lbs trailer, total weight just over 14000 lbs.

tgui

6l80 in a nnbs is a nice setup. I've had a built 4l80e and stock 4l60e in a nbs. For stupid strength I'd go 4l80e. For a close second in strength and WAY nicer driveability the 6l80. 6l80 just needs a really good and experienced tuner.

tgui

No personal experience but I've read that superchargers are great for occasional power. Sustained usage on long pulls can really heat them up and damage them, thats why tow rigs use turbos.

Once again, just what I've read.