i have a 91' k1500 chevy..i have just installed a 3" body lift and a 6'"
sus lift...i am wondering whether or not to swap my 373 gears gor good
'ol 410's ..i will be running 38.5 x 14.50 15 swamper boggers and will
be mostly off road use..mud racing also...do you think that would be a
more suitable gear for this purpose...btw it is being powered by a
383...498 horse small block...thanks

On Sat, 4 Feb 2006 01:34:14 -0500, nars058 (AT) webtv (DOT) net (NiKoLaS) wrote:

Were this my truck, only off-road (mostly off-road) with no
significant high speed highway driving, I'd go for at least a 4.56, or
a 5.11 gear. Maybe even more... My Hummer H1 (6.5 diesel) is about
5.35, with 37 tires. With a taller tire you may want more...

Many factors matter, such as what transmission, engine specs, etc. No
one single true or reasonable answer...

thanks for the help....i have actually decided to go with 4.56
gears...figured i couldnt go wrong with those...

Using the RPM calculator at Randy's Ring & Pinion's website as a guide,
I'd say 4.56's are the bare minimum.

With 38.5" tires at 60mph, it would put your engine speed at 1671rpm in
overdrive. That's close to my engine speed with 3.73's and 31" tires
(1698rpm) so you should be good with the 4.56's.

~jp