OK, folks, I'm looking for some knowledge. My 56 1/2 ton has the standard 3.93 rearend, which gives me about 3500 RPM doing 55 mph. I'm hoping to find a 3.23 or lower (or higher, depending on your frame of reference) that will cause less of a strain on my Thriftmaster. Equally important is keeping the 6-bolt hub so i don't have to run different wheels. HELP!!
get a new gm metric rear end and run 3.08s or a old ford 9" from like a ranchero and run a 3.08 gear set both axle hubs can be drilled to your 6 bolt set up i'm doing a 9" myself
Drilling out 6 holes where there are already 5 - sounds like a tricky deal. I can't use my Chevy drum, can I? It seems like there would be overlap of at least one of the holes, and they would have to be drilled perfectly perpendicular or the lug nut won't seat right. What am I missing?
that is way you weld the stud holes up first then drill your six holes and i had access to a drill press with a hole in the center of the plat so the axle fit in it perfectly and yes you can use the drums as a template to drill for your new six bolt bolt pattern.
That's the missing piece - weld filling the holes. Of course, it would 't hurt to have the monster press you found, but it's a start. Thanks for the tip. By the way, what will you have to do to get the yoke to work on your drive shaft?
You can get differant size yokes thrue summit racing for the ford 9" or one can change the yoke on the drive shaft but will need to be welded in by a machine shop
or get you a 10 or 12 bolt out of nova or chevelle or chevy truck you'll have to re set pinon angle and re weld spring purches !!! then run 54 car hubs in the front which will make it 5 lug all the way around ? on the rear end measure from backing plate to back plate make sure its close to what you have ? somewhere around 53-55 inches cant remember ? unless you can find a 1969 or 1970 chevy pickup 12 bolt with leaf springs its allready 6 lug and bolts right in !!!!! thats whats in my 1958 suburban !!!!!!! i got lucky with that one !!!!!! 300 bucks complete !!!!!! p.s any good machine shop can redrill your axels and balance them for you !!!!!!
a stock 12 bolt will handle a good moter a a 10 bolt IS ONLY GOOD FOR ABOUT 350HP STOCK!!! If you have a moded moter this rear end will need to be FULLY BUILT just ask any Syclone/Typhoon, or V8 S-10 owner These are very good rear end but need to be built first. Without building the stock 10 bolt well heres how they break in halve LITRAILLY 4.3 V6 Turbo+25psi boost+4L80E+torque braking=a broke in halve rear end and oil all over the ground!!
The easiest is to just use the Borgwarner overdrive trans. It will bolt in as a direct replacement to your 3 speed, use your shift linkage, very available, easy to wire, cheap, and a full 30% overdrive. Used with your 3.93 rear end this will give you a final of 2.75 when in 3rd gear. There should be several at the Arlington swap meet this week end for around $125 - $150. GM used them in cars and trucks from 55 to up in the 70's.
