The Stovebolt Site Forums The Shop Area Engine Shop 1951 Chevy 3100 rear end swap question

Hi y'all
Well, another driving season is here for our old Chevy. This year, we've got some $$$$ set aside to do SOMETHING about making it more driveable on the highway.

Our truck is bone-stock and in very good condition. The brakes work well, the original 216 cid engine runs great, (I believe it was dealer rebuilt a few years ago) and the 3 speed transmission works well other than a minor leak back by the bell seal on the torque tube.

Here's my question: I want to change to a more practical rear end ratio. Right now, top speed is in the 45-50 mph range. I'd like to bump that up about 10 mph so 55 mph would be a reasonable cruising speed. The truck is very original, and I don't want to do anything that detracts from its value. The way I see it, after searching on this forum and reading tons of good info, there are two ways of going about it.

1. Order all the needed parts from Patrick's and tear into it. I'm familiar with dial indicators and understand (mostly) about preload and backlash, etc. My main concern here would be struggling with that %#**!* torque tube.

2. Swap out the whole 3rd member to something more recent with an open driveshaft. I'm aware that there are lots of options here, including S10 and Task Force rear ends. Here my concerns would be:
a) What do I have to do to my 3 speed to convert it to open driveshaft?
b) Can I keep my emergency brake setup?
c) How much work to end up with the right length driveshaft?

I'm not a welder, but there is a good weld shop right around the corner from our house. If I went the swap out the rear end route, I'd want to keep the original 3rd member and torque tube so the truck could be restored to original if need be.

I'd appreciate some input from you guys that have actually done either the Patrick's kit or rear end swap. OK, I'll go back to searching the archives now.

Thanks

As far as driveshaft, this web site will give you an idea as to what you will need to do to put in a new one. http://www.iedls.com/ They also sell them through SummitRacing.com .

I have done a few rear ends. The latest is an early 70's Chevelle / GM 10 bolt in my 1952 Suburban. This one I converted to rear disc ( for about $100.) Last one I did, I solved the parking brake problem with a driveline brake. This one, I will find the proper cables to work with the original brake rod. I know there are a few businesses that custom make cable, plus there are kits you can buy to make your own from the likes of Lokar or Gennie. Don't know if the three speed can be converted, I've always had later model transmissions.

I probably just generated a bunch more questions for you!!!

Fred
The torque tube 3 sp speed tranny cannot be converted to an open driveline, you will have to get a later model 3 sp to go to an open driveline. Changing out the rearend for your truck will involve, new tranny, fabricated driveline, replacement rearend, welding up new spring perches, and mix and matching parking brake cables. In my opinion, if you have a bone stock truck, I would go the the Patrick's ring and pinion set-up to keep it looking stock and yet more drivable. If you had a hodge podge truck with various later model upgrades (like my '50) it would be a different story. It is obviously up to you, but I see fewer and fewer original trucks out there. Just my .02,
Steve O

I arrived at the same decision as Nifty 50 suggests. I called Patrick's today and ordered the ring and pinion and the installation kit. Talked to "Phillip" - nice guy, he offered free shipping for all that iron.

I'll let you guys know how it all works out.

BTW, what options are out there to correct the speedometer reading after this change?