Anyone shorten a rear to optimize a wheel/tire combo in an uncut A body?

[DGrace]

I have a '73 Dart that came with a 7 1/4 rear and want to go with an 8 3/4. Considering a Moser fabricated unit but not sure of the length? I have Centerline Warrior wheels - 8 x 15 w/ 4.5 backspace and Mickey ET Street Radials. With the wheel/tire centered in the wheel well and as square ad I can get it, I measure 55 5/8" mounting surface to ms. I've measured several times and come within 1/16" each time. I've read where others have used a similar size wheel/ tire combo on a stock A body 8 3/4 (57 1/8") with no interference issues - maybe an offset hanger kit. Don't see how that can be since my measurement is 1 1/2" shorter? Wondering if anyone has done something similar and if my measurement is accurate? It's rather pricey and I can't afford to mess up. Any help is greatly appreciated.

 

[Syleng1]

If you speak to a tech rep at Mosier- tell them your measurements. Yes for that much money you should get it right. The a-body 7-1/4 rear will interchange with a a-body 8-3/4 rear. If your wheels fit, just tell them you have a stock a-body and are looking for a stock length A-body rear. I would also verify that the wheel face to wheel face measurement is the same so the wheels do not move in location and hit a wheel well lip.
Personally a used a-body 8-3/4 can be had for less money unless you need something specific or want a certain look.

Good luck in your quest!
Joe

 

[DAndy ART]

Talk to Cass at DR DIFF. Super guy, great product, great service.

 

[69_340_GTS]

My guess is that the 8" wheels with only 4.5" backspacing are the issue. Are those guys with stock rear axles using wheels with 5" or more backspacing? I know I'd have to to get the tires centered in the wheel wells.

 

[SLOPAR72]

If you are willing to spend the money on any rear with the word "Fab" attached to it take the time to mock your wheel/tire combo in the wheel wells for spacing (both X and Y) and the company will help you with the measurement. That's how I did it in a Chevelle and it was a one and done deal.....

JW

 

[DGrace]

Talk to Cass at DR DIFF. Super guy, great product, great service.

I talked to him but they just offer an S60 and I'm not very familiar with them and it's probably overkill for my engine budget.

My guess is that the 8" wheels with only 4.5" backspacing are the issue. Are those guys with stock rear axles using wheels with 5" or more backspacing? I know I'd have to to get the tires centered in the wheel wells.

I did. Measured several times and get 55 5/8". That's 1 1/2" shorter than an A body 8 3/4 rear. Just wondering if anyone has shortened one to try to optimize the stock wheelwell/frame space? Thanks for the reply.

 

[DGrace]

If you are willing to spend the money on any rear with the word "Fab" attached to it take the time to mock your wheel/tire combo in the wheel wells for spacing (both X and Y) and the company will help you with the measurement. That's how I did it in a Chevelle and it was a one and done deal.....

JW

From what I've seen, a MO875 is as cheap as buying a used one and shortening it. Plus it's stronger and is still "MOPAR". My ET Radials are mounted on my 8x15 4.5 bs Warriors and centered in the wheelwells. My measurement is 55 5/8" wms-wms. Just wondered if anyone has shortened a rear to optimize the factory space? I don't want to mini tub and would rather not do a spring relocation kit - offsets would be ok. Trying to accomplish that with the shortened rear/ wheel combo. Thanks for your reply.

 

[SLOPAR72]

From what I've seen, a MO875 is as cheap as buying a used one and shortening it. Plus it's stronger and is still "MOPAR". My ET Radials are mounted on my 8x15 4.5 bs Warriors and centered in the wheelwells. My measurement is 55 5/8" wms-wms. Just wondered if anyone has shortened a rear to optimize the factory space? I don't want to mini tub and would rather not do a spring relocation kit - offsets would be ok. Trying to accomplish that with the shortened rear/ wheel combo. Thanks for your reply.

You are heading in a direction worthy of a custom cut rear IMO. You get it all with buying a housing exactly the way you want it. Using my Chevelle as a reference I was able to comfortably get 295's in the rear and not rub using the exact rim I wanted plus having the front to rear tire stagger we desired. You have the rim and tire combo so that is half the battle.

Good luck,
JW

 

[DGrace]

If you speak to a tech rep at Mosier- tell them your measurements. Yes for that much money you should get it right. The a-body 7-1/4 rear will interchange with a a-body 8-3/4 rear. If your wheels fit, just tell them you have a stock a-body and are looking for a stock length A-body rear. I would also verify that the wheel face to wheel face measurement is the same so the wheels do not move in location and hit a wheel well lip.
Personally a used a-body 8-3/4 can be had for less money unless you need something specific or want a certain look.

Good luck in your quest!
Joe

My wheel/tire combo is very close to the fender lip so I figured a shorter rear would center it better. I measured 55 5/8" wms-wms - a stock A body 8 3/4 is 57 1/8" so that's not ideal. I love the look of the MO875 and it's as affordable as a reworked stocker and stronger - and still MOPAR. Just wondering if anyone has shortened a rear to optimize the factory space. Don't want to mini tub & would rather not do spring relocation kit - offsets are ok. Thanks for your input.

 

[DGrace]

You are heading in a direction worthy of a custom cut rear IMO. You get it all with buying a housing exactly the way you want it. Using my Chevelle as a reference I was able to comfortably get 295's in the rear and not rub using the exact rim I wanted plus having the front to rear tire stagger we desired. You have the rim and tire combo so that is half the battle.

Good luck,
JW

Thank you. Praying my measurement is accurate.

 

['Cuda_ragtop]

Did you make your measurements with the leaf springs in place. That way you can see if you will need offset hangers and relocated mounting perches.
I mounted the leaf springs and lowered the car onto the springs to compress them.
Dr. Diff 1/2" relocation hangers and perches moved inboard 1/2" each for my narrowed 8-3/4.
Different car and wheels but same goal.

 

[DGrace]

Did you make your measurements with the leaf springs in place. That way you can see if you will need offset hangers and relocated mounting perches.
I mounted the leaf springs and lowered the car onto the springs to compress them.
Dr. Diff 1/2" relocation hangers and perches moved inboard 1/2" each for my narrowed 8-3/4.
Different car and wheels but same goal.
View attachment 1715063502

No, all measurements were taken with the rear and springs removed. Dropped it as low as I could go (with me still under it) and verifying the wheels were centered.Hoping that Dr. Diff offset kit will work but may be too close to the housing ends? - that's the next "challenge". Getting ready to order and seeing if anyone has done it & could offer some help. Thank you.

 

[DGrace]

No, all measurements were taken with the rear and springs removed. Dropped it as low as I could go (with me still under it) and verifying the wheels were centered.Hoping that Dr. Diff offset kit will work but may be too close to the housing ends? - that's the next "challenge". Getting ready to order and seeing if anyone has done it & could offer some help. Thank you.

What was your rear measurement after shortening? What size wheel/tire are you running? Not sure how similar the Dart & Cuda are as far as room?

 

['Cuda_ragtop]

What was your rear measurement after shortening? What size wheel/tire are you running? Not sure how similar the Dart & Cuda are as far as room?

56" rotor face to rotor face set up with Cherokee Rear Disc Brakes
51" rear end housing, flange to flange
17x9" Year One Mopar Rallye Wheels, 5" Back space, 275/40R17
Backing plate and rotor hub are a little thicker than drums...
Worked out the dimensions with Dr. Diff and Bill Scribner. Their math came out the same!
Scribner is narrowing my housing.
Custom Axles, Offset Hangers and new perches from Dr. Diff. He doesn't narrow housings anymore but still sells stock length.

 

[DGrace]

56" rotor face to rotor face set up with Cherokee Rear Disc Brakes
51" rear end housing, flange to flange
17x9" Year One Mopar Rallye Wheels, 5" Back space, 275/40R17
Backing plate and rotor hub are a little thicker than drums...
Worked out the dimensions with Dr. Diff and Bill Scribner. Their math came out the same!
Scribner is narrowing my housing.
Custom Axles, Offset Hangers and new perches from Dr. Diff. He doesn't narrow housings anymore but still sells stock length.

Sounds close to me - 55 5/8" wms-wms.

56" rotor face to rotor face set up with Cherokee Rear Disc Brakes
51" rear end housing, flange to flange
17x9" Year One Mopar Rallye Wheels, 5" Back space, 275/40R17
Backing plate and rotor hub are a little thicker than drums...
Worked out the dimensions with Dr. Diff and Bill Scribner. Their math came out the same!
Scribner is narrowing my housing.
Custom Axles, Offset Hangers and new perches from Dr. Diff. He doesn't narrow housings anymore but still sells stock length.

Sounds close. Stock A body is 52 5/8". Mine should be 1 1/2" shorter or 511/8" flange to flange. Gonna pull the trigger....... Thank you.