It's a Jukebox. 1953 AMI 120 songs. I thought you were hip to Jukeboxes. I read your profile. Never mind. Not important.
As far as 55-59 diff, you will have to do your homework. Widths are all online. Measure yours and see what comes close. 55-59 is pretty close. If I was switching over to open, I would try to go a little newer than that. 12 Bolts
are good and come in 3.73 which is the perfect ratio for acceleration and Hiway mix. Your truck width will be in the 60" range.
Wheel
Mounting
Surface to
WMS.
Also regarding what affect ratios have: there are "fill-in" calculation formulas and
charts on line, to see various combinations for speed, mileage, acceleration, etc.
As in any proposed modification, you have to search the internet. Stovebolt is a good place to search and to ask those questions about what is involved/transmission/what fits what. Members who know what parts to get will advise. I think 52Carl has a very good grasp of this. Lots of "car" 5 lugs rears but not too many 6 on 5.5 lug patterns from a truck.
Not to over simplify but the basics are:
Make sure you know what components for your motor or your bell housing to use. Work your way back to diff. Buy the parts. That always helps to see the way forward. It gives you things to measure and contemplate. Sell the old diff and other parts to recoup funds.
Rip out the old and put in the new. In the rear, you are going from leaf to leaf. That's a matter of spring perches being welded on and tightening the U-bolts. Hook up brake line and Ebrake cable. The line is easy but the Ebrake may take some thinking. When rear end is installed and it's yoke is "aimed" correctly for pinion angle, and new or old tranny is mounted, measure and have a drive shaft made or modified.
It's planned out just like any other "home" project as I see you are aware.
I found
This in our search function.
I have found that sometimes an automatic trans is very nice. Easier to install, no clutch, plenty of acceleration and overdrive. You do lose that manly tactile shifting feel however.
