Thread: Rear end width & set up help needed

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Happy fathers day, guys! I bought a rearend for my Plymouth last week, spent two days cleaning, disassembling, and painting only to find out that I read the application book wrong and it's 2 1/2" inches narrower than the stock one. I was thinking of moving the spring perches out and using a wheel spacer and maybe a shorter backspace on the rear wheels. What do you guys think?

I don't know exactly what your plans are, or what you are working with, but know I am having a rear end cut right now to go with bigger wheels and try to minimize the backspacing, to give the rear wheels more depth. Might be that it will work out for you, if that is a look you are going for.

Red

Keep going with your attitude there. General rule of thumb....More back spacing creates better launching for Drag racing and getting off of the line from light to light. Less back spacing creates a better, more stable ride for cruising down the road.You can do this well and make it work with little complications.

i would try not to use any spacers . try to fix it with rim off set if you go with a wider rim then you may want to move the springs in the springs are sometimes the first thing that will hit the wider wheel

Sorry to hijack, Nitro I'm probably going to end up with about half and half, 4.5-5" of backspacing on a 10" Budnick wheel, will that pretty much give em a good balance? The truck is just getting setup for light to light and cruising to the drive-in.

Red

What I was hoping to do was find a rearend that was the same width and would drop right onto the factory 47 Plymouth springs. This is just going to be a nice cruiser, nothing for the dragstrip. I had a book on 34-50 Mopars and it said that a 78 Granada rear would do that, but I read the book wrong; they were talking about 34-37 applications. Of course I didnt measure, I just went out and bought one, cleaned it up and tried to bolt it in. If I move the spring perches on the rearend it will physically fit, but the backing plates are really close to the springs and the frame. I don't know if I should just look for a rearend the right width (55" between the backing plates), or move the springs in, or try some creative backspacing on the wheels. Don't you hate when you make a really boneheaded move and it costs you a couple days work?

Originally Posted by falconvan

What I was hoping to do was find a rearend that was the same width and would drop right onto the factory 47 Plymouth springs. This is just going to be a nice cruiser, nothing for the dragstrip. I had a book on 34-50 Mopars and it said that a 78 Granada rear would do that, but I read the book wrong; they were talking about 34-37 applications. Of course I didnt measure, I just went out and bought one, cleaned it up and tried to bolt it in. If I move the spring perches on the rearend it will physically fit, but the backing plates are really close to the springs and the frame. I don't know if I should just look for a rearend the right width (55" between the backing plates), or move the springs in, or try some creative backspacing on the wheels. Don't you hate when you make a really boneheaded move and it costs you a couple days work?

Even if you move the springs inboard, you still have the issue of the backing plates/frame clearance to deal with. In my opinion, I'd chalk this one up to "lessons of life" and find the proper width rear.

If you have to move the spring pads on another rear, be advised that welding the pads in another location can introduce enough heat into the housing to warp it, resulting in wheel bearing problems and other issues. If you use an acetylene torch to heat the remainder of the housing circumference or just continue running the weld bead all the way around, most of the time you can get pretty close to straight.

Falcon good thing is Vintage Mustangers are looking for this rearend to V-8 them. So moving it should be fairly easy and get your money back and maybe make a couple bucks.

I ran into allmost same situation only mine being a little wider . Fortunatly the wheel i choose has a large enough offset that corrected my problem .

Thanks for the good advice, guys. I went to the boneyard this morning with a tape measure and came home with a 87 Dakota rear that is the perfect width. Just need to move the spring perches a few inches and it'll drop in place. There's a freshly painted and disassembled 78 Granada 8.8 on Ebay right now if anyone's interested.

I think you made the right move and the best decision.

Go back to the boneyard and get the driveshaft. You'll need the rear joint when you make up your new driveshaft.

What is width of the Dakota from axle to axle? I have a 48 ply coupe and I put a diff. from a 1979 camaro in it. Had to do the spring pads. I am now looking for something to put in a 48 chevy coupe.
Thanks Rex

Hey Rex,
It was 54 1/2" between the backing plates. Someone told me when I move the spring perches, I have to have the body on the frame to correctly set the pinion angle because of the loaded weight. Anyone know how to do this? I was just going to move them out a few inches in their stock locations. Sorry for all the questions, it's my first.