8.8 Mods By 1946Austin

7722 Views 13 Replies 7 Participants Last post by 1937Austin, 1 mo ago

ProMetalShop

Discussion Starter · Apr 1, 2013

The Following Info was written by Vall (1946Austin)

On the rearend- I started to do a 9" Ford, but then discovered the 8.8" Ford rearends. They are plentiful, cheap, lots of great ratios, limited slip, and a great choice to narrow cheaply! I bought a 3.73 posi 8.8" for $175 from a 1993 Expolorer. If you want 4 wheel discs, then get a 1994 or later, as they went to disc in '94.
The third member is offset 2" to pass. side, so if you want to narrow it you simply buy a pass. side axle shaft and then cut the driver's side housing down 4" to fit the new shaft. Drop the shaft back in and you've got a rearend that's a little narrower than a stock first gen Mustang, and cheaper than a 9" too. The 8.8" is a copy of a 12 bolt GM, but with 31 spline axles instead of 30 spline. It will also give you 5x4.5" bolt pattern to match the Econoline straight axle. You'll still have to move the springs inboard if you want to tuck the tires, and I'm not sure what that will entail as I left my axle at 58" overall, so my tires would hang out a couple inches on each side. I like the look on an old school type gasser.
One last thing' If your '65 Mustang still has the single bowl master brake cylinder then you'll want to upgrade to the dual reservoir from a later Mustang too. The later is a bolt on so no mod, but you will need to split the lines to the rear and add a manual proportioning valve in the rear line, so you can adjust the pressure down on the rear after adding discs. Even if you didn't add discs you'll still want to do the master, but without the valve, as it makes a better braking system.

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37hemidodge

· #2 · May 8, 2013 (Edited)

Stoped buy a yard today there looking for $200 each sounds very reasonable to me .Val I remembered your post with this and it stuck these are considered a strong rear and a great alternative to a 9" or a 8.3/4 .what was your measurement from backing plat to backing plate after you chopped it ? I think I'll go snag one sat.if I have time. Thanks Val

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37hemidodge

· #3 · Sep 18, 2014

Ok guys now I know this is not a mustang site but you guys are not the judge type

. My sons 2000 stang had a rear end noise so I pulled the cove and bam in my face !

Automotive lighting Motor vehicle Hood Automotive tire Automotive design

My question is replace the whole rear end ? Prob easier than messing with the gears ?
Or get the replacement goods and rebuild it

I have never taken one apart or put one together back in the day it was always voodoo don't even try just replace it

This is a 8.8 373 28 spline .
I just replaced the motor in June this is my oldest sons ride .
Thanks for the help guys

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1937Austin

· #4 · Sep 19, 2014

Not sure I'd waste time rebuilding that one, unless the Mustang with smaller axles isn't available cheap. I would take some measurements too, and see if there's a chance the 2WD Ranger 8.8" with 28 spline axles is the same width, and same perch location. If they are, that will be a second option.
Looks like he lost his pinion bearings to cause that pinion gear to move rearward and contact the posi unit.
I just noticed you asked way back in May about a measurement from backing plate to backing plate "after chopped". I didn't chop mine down, so don't have that measurement. But if I had, the rear is about 51.75" between backing plates now, so take 3" off of that. Overall width is 59.5" to wheel mating surfaces on the drums, so they end up 56.5" with the 3" short side axle tube chop.

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37hemidodge

· #5 · Sep 20, 2014

Thanks Val . I need to take it apart to see if the housing was damaged at the pinion bearing are if not I think I'll get a 2nd posi unit and new gears also . I have a friend of a friend that dose rear ends I'll see if I can get him to assist with that. If the housing is toast then a new bone yard rear will be next option .

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1937Austin

· #6 · Sep 20, 2014

Not sure I'd replace the posi unit, unless you think the housing is damaged too badly to reuse. It looks superficial, and most likely just needs a ring and pinion, and bearings to get it going again. If you have to get a new posi unit, you'll end up over $1,000 with the posi, R&P, bearings, and labor.

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dsb

· #7 · Sep 30, 2014

Hey Vall, can you stick different axles in those rear ends to allow chevy bolt patterns? I want one of those rear ends, but I have the 15x10 cragar ss rims set up for chevy bolt pattern.

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1937Austin

· #8 · Sep 30, 2014

dsb said:
Hey Vall, can you stick different axles in those rear ends to allow chevy bolt patterns? I want one of those rear ends, but I have the 15x10 cragar ss rims set up for chevy bolt pattern.

I'm sure you could buy aftermarket axles to fit Chevy pattern, but it would be cheaper, and easier to re-drill the Ford axles to the Chevy pattern. Here's a link for Rotten Leonard's drill pattern kit. It's $89 plus $8 S&H, and works very well. Cheaper than taking your axles to a machine shop and having them drilled for $12 a hole. If you keep the drums on the axle shaft it will drill both at the same time.
http://www.rottenleonard.com/Menu.html

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37hemidodge

· #9 · Sep 30, 2014

Sorry for the late reply been busy around here

. The posi is cracked in half so need a new unit also. It seems like it is not too crash to replace it . He really wants the 410 gears also it was 373's and from what I have believe happened was the gears were replaced but did not replace the crush bushing so it could not be torqued properly ! After enough reading to be dangerous I thought I would give it a shot . Unless others say nooooooooo!

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1937Austin

· #10 · Oct 1, 2014

Haven't tried a 8.8", but tried a 12 bolt GM back in the 70's with dismal results for me then. It scared me off trying again, but the internet has such good help I might try one some day.

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mt94ss

· #11 · Feb 17, 2015

Hey Vall, decided to go and get an 8.8 for the '55 instead of the 10 bolt that's in it. I got a new one with disc brakes 3.73 and posi on half-price day for $80! my question is the big weight that is hanging off the right side of the third member (where the third shock mounted). Did you leave this on? Does it help with vibration or something? Also can you post here about the driveshaft mod that you did. I thought that I remembered that you took it in and it was no big deal to have a GM front and Ford rear.

Thanks!

Mike

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vht

· #12 · 2 mo ago

I'm no ford guy, worked for them 18 yrs, but the 8.8 rear is one nice strong unit. It's stouter than the 12 bolt and super easy to set up. I've narrowed several and set up over a 100. Quick Performance has real good prices on everything for them. I done a 2016 Super 8.8' ford calls it that, not me, and that was the biggest head ache I've ever done, I think the super stands for a super pain in the a$$. I weld the tubes on the explorwe rear ends and trim off all the brackets and excess around the center section to make them look better. All the axles in them are 31 spline and if you have the disc brake one, you don't have to worry about the C clip axle coming out if it did break. I got one in my 57 chev and the next one foe it will have big ford ends on it.

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technishien

· #13 · 1 mo ago

One last thing' If your '65 Mustang still has the single bowl master brake cylinder then you'll want to upgrade to the dual reservoir from a later Mustang too.

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1937Austin

· #14 · 1 mo ago

technishien said:
One last thing' If your '65 Mustang still has the single bowl master brake cylinder then you'll want to upgrade to the dual reservoir from a later Mustang too.

I think it really doesn't matter if what car you're building, if it's got a single pot master everyone should upgrade to a dual reservoir master, unless it's a concourse restoration where it needs to stay stock.

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