Late model rear end

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smythge

65 with a BIG BLOCK
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I am wondering if anyone has ever used or done any research on a late model rear end in their A-body? Maybe an SUV or truck, there are tons available in the junk yard for cheap which I am sure could be altered easly enough to fit. I would think there would be some decent ones out there. Give me your thoughts or suggestions on this.
 
I believe the Ferd Explorer has the 8.8" rear end and the width should be right for an A body. I imagine you'd have to change the spring perch locations to make it fit. These things come with a pretty impressive array of good gear ratios and a lot of them have the (posi) rear ends, for want of trying to remember the correct Ferd term for their suregrip. :) Another one that might work is the Jeep Cherokee diffy, although I haven't measured one for width.
 
Did some research and the explorer rear ends are a little bit longer but indeed are 8.8" (replaces the 9") I found one out of a 1997 with 60k, is a posi (locker) with 3.73 gears, disc brakes and 5 on 4.5" bolt pattern, for $175.00. The only thing I can see having problems with is the drive shaft other than that Is there any reason I wouldn't want to do this? an 8.75 out of a mopar with drum brakes is going to run me over $500.00 and probably still need some work.
 
Dude, you're working fast. :salut: The only thing I can think of at the moment is to ensure that the center carrier is centered in the rear housing same as the 8.75 Mopar. I believe some Ford diffy's had the carrier ofset to the right? Definitely NOT a Ferd expert. :silent: The measurements on the Mopar 8.75 should be 52 5/8" flange to flange, and 57 1/8" drum to drum, so you can check the Explorer one against those measurements to find the exact width difference. With the 5 x 4.5" large bolt pattern you have a great deal of latitude in rim selection, and a larger rim offset should make up for the width disparity, if it's not too great. As for the driveshaft, you should be able to find a U-joint that will fit the Mopar driveshaft and the Ford carrier pinion yoke. If you decide to go this way, let us know and I'm sure I or someone else can find you the correct U-joint interchange number. Keep us posted, and good luck. :thumblef:
 
Yeah I was thinking about the carrier and they're offset 2-3/16" to the right, any idea what the maximum horizontal angel the drive shaft can be at before I run in to problems with the U-joints? Also what if I narrowed the long side by 2-3/16th that would solve the centering problem and make the rearend almost an exact fit?

Here are the specs on the rear end:


Donor Vehicle = '97 Ford Explorer

Factory Gear Ratio = 3.73

Axle Shaft = 31 spline

Axle Diameter = 1.32"

Ring Gear Diameter = 8.800"

Traction Action = POSI-Traction

Brakes = Disc Brakes

Axle Strength Each = 6,500 lbs. Before breakage

Total Length = 59 3/4" Which is about 2" longer

Axle Tube Diameter = 3.25"
 
O.K. let's see what we can come up with. First: Mopar A bodies have the engine / tranny combos offset to the right to aid in exhause clearance on the steering box (left) side. You may be able to get away with this by bringing the rear slightly back to the left when you weld on your new spring perches - say split the difference? That should clean up the horizontal plane. Just guessing and desktop engineering here. :)

Second: If that total width is drum to drum, then you have exactly: 59.75" (Ford) - 57.25" (Abody) for a total of 2.5" difference, or 1.25" wider per side for the Ford. That should be easy to compensate with proper wheel backspacing.

Third: Tube diameter is 3.25". I'll have to check, but I believe the Mopar 8.75 rear end has 3.0" O.D. tubes. That might cause a minor problem with the spring bottom plate / shock mount but would (should) be very simple to work around. :)

Hell, for $175.00, go for it.
 
Thats what I wanted to hear! I'm going to pick it up tomorrow and work on it this weekend, I'll let you know how it goes!
 
Just think: 5 x 4.5" wheels, modern disk brakes on the rear, 3.73 Posi, almost unlimited choice of wheels from 15" on up; hmmmmm :salut: Do me, and a lot of other folks on here, a BIG favor and document the process and take LOTS OF PICTURES! :thumblef: There are literally millions of those rear diffy's out there just waiting for a real home - like under an A Body. Good luck.
 
I would be concerned with the pinion and trans not being inline. You are going to have two angles to deal with. The drive line could possible hit the floor also. I would suggest contacting a race car chassis manufacturer on the compound angle drive line. These guys do this stuff for a living and will have the definitive correct answer instead of us home brew engineers deciding what is right. Some day some one else may own these cars we work on and we don't want a time bomb just waiting for the right moment to go off and possible hurt someone.
 
340mopar, you have a couple of valid points there, especially with the angles on the pinion lining up on the horizontal plane. On the vertical, you have to set your pinion angle the same as you would with any rear end swap. There's always the possibility of being out of line with the tunnel and hitting the floor boards, but mocking it up should determine if that will be the case.
 
Nothing a torch some steel and a welder can't fix.
 
I be watching, I thinking of a Mopar 9 1/4 and cutting it down to size. Any imput froms other is welcome> Den
 
smythge said:
Nothing a torch some steel and a welder can't fix.
Click to expand...

That's kind of my plan of attack when I'm going somewhere no man has gone before. But in this case, there's thousands of Ford 8.8 & 9 " rear ends under all different modes of Chivvies, Mopars, foreigns, compacts, sub-compacts, and, yes, even a few Ferds. Keep us updated. :salut:
 
the left to right drive shaft angles must be the same at the tranns and the diff, it may be nessary to move the tranny a small amount one way or the other to get the needed angle, if these angles are not the same the u-joints will fail early, vibration may also be caused by the miss-alignment....
0ther than that you should have no problems....this info comes from Chassis Engineering .....
 
My plan to align the transmission and pinion is to narrow the long side of the rear end by about 2 inches, this will solve 2 problems: 1. The pinion will now be centered with the transmission 2. The rear end will be the exact same width as the original. What I am wondering is if I can get another right side shorter axle and use that in narrowed side instead of having the exisiting one shortend by a machine shop.
 
You can use the shorter axle in the other side. You are not supposed to switch sides on axles after they have already had stress in one direction. But given the lack of power in an exploder I wouldn't worry about that. Of course a new short side axle would be best. We used to do this exact thing in the 70's. The early 70's Econoline 1/2 ton vans had a 9" with an offset. The short side axle was about 25" long. We would shorten the long end on the housing and use two short end axles making a rear about 52" wide. The only drawback was the large 5 x 5-1/2" bolt circle, if you call that a drawback.
 
Someone help me out with a place to get a conversion U-joint for the swap.
 
I picked up the rear end, the one they quoted me on was not out of the car so they gave me one from a car with 25,000 miles. Also got the shorter right hand axle, but the rotors are really rusty and they didn't have the calipers. So I need to invest a little more in those. Saturday I will get the rear end cut and welded and put the shorter axle in and work on the perches and shock mounts and do a mock fitting. I'll post some pics and an update on the progress
 
Be sure to check the center line of the chassis and the center line of the motor -tranny..... you will most likely find they are not the same... when I did my last one I put two lines on the concrete floor under the car, one for the center of the chassis and the second for the center of the motor -tranny.. they make for easy referance when setting up the lateral drive shaft angles. . i would do this before i started cutting the new rear end . you may find out that center of the axle isnt what you actually want.. measure twice,,, cut once..... good luck.
 
Ok I figured out the U-joints. Spicer makes a flange to a 1310 U-joint conversion yoke, then they make a 1310 / 7260 combination u-joint So here is my total so far:
rear end $175.00
a second shorter axle for $25.00
Rotors turned $25.00
New Calipers $65.00
Brake pads $25.00
Combination U-joint $22.00
Spicer flange to yoke $31.00
Misc hardware & fluid $32.00
___________
$400.00

Not too bad for a 8.8" posi rear end with 3.73 gears 5 on 4" bolt pattern & disc brakes, now I just need a set of wheels.
 
It sounds like you're keeping everything well within a reasonable budget compared to even an 8.75 A body rear end. Keep us posted on final results, and don't forget the photos and step-by-step disertation. :)
 
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