Dusterbd13-michael
Dusterbd13-michael MegaDork
5/2/22 8:00 a.m.

Looking at rear end options for the cup car. 

One possibility is a ford explorer 8.8

Cheap, right gears, right width, ttack lock. 

However, pinion is offset from center by 3 or so inches. Cup car is designed for centered according to my tape measure. 

Will this cause problems? I know about equal/opposite for vertical plane on the driveshaft, but no idea on horizontal. 

gearheadmb
gearheadmb UltraDork
5/2/22 8:34 a.m.

Just keep the pinion shaft and trans out put shaft parallel and it should be fine.

Ranger50
Ranger50 MegaDork
5/2/22 12:05 p.m.

You can hack the long axle and use a short axle to make a centered housing.

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/2/22 12:09 p.m.

In reply to Ranger50 :

Narrows it too much for the application, unfortunately. 

slantsix
slantsix HalfDork
5/2/22 12:19 p.m.

People routinely Use Ford 8.8's in Mopars..

 

Get 2 Short side Axles and then Shorten the Longer axle tube to match the other short tube.

We are doing that for our Lemons car now as we destroyed the (weak) MoPar 7.25" Rear during the last race.

 

Greg

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/2/22 12:23 p.m.

I know i can. Problem is that the current axle is 58.5 wheet suface to wheel surface. Not much room to go narrower due to truck arms...

eastsideTim
eastsideTim PowerDork
5/2/22 12:33 p.m.

Some S10 guys use the 8.8 in an offset position without cutting it, and don't seem to have problems.  I gather it helps when using wheels with modern offsets(and it's less work).  I'd assume if the angle is not beyond what a u joint can handle, you'll be fine.

 

APEowner
APEowner GRM+ Memberand SuperDork
5/2/22 12:44 p.m.

Why are you not running the rear end that's in it?  I would think that by the time you modify pretty much anything else to get the right track width, bolt pattern and brakes you'd be money ahead to just get a 9" center section and axles.  Plus you'd be giving up the full floating rear.

eastsideTim
eastsideTim PowerDork
5/2/22 1:09 p.m.
APEowner said:

Why are you not running the rear end that's in it?  I would think that by the time you modify pretty much anything else to get the right track width, bolt pattern and brakes you'd be money ahead to just get a 9" center section and axles.  Plus you'd be giving up the full floating rear.

Didn't realize there was a 9" housing there already.  Duster, if you want, I can keep my eyes open for a 9" center chunk in a yard up here.  Every now and then, a 70's Ford pickup turns up, and I assume it'd have deep enough gears.

RacetruckRon
RacetruckRon GRM+ Memberand Dork
5/2/22 1:12 p.m.

Let me know if you want to get rid of the 9" housing

RacetruckRon
RacetruckRon GRM+ Memberand Dork
5/2/22 1:19 p.m.

Bronco 8.8 were also 31 spline like the Explorer diffs.  I think they were an inch or two wider and I think they were drum brakes but don't quote me on that.

Dusterbd13-michael
Dusterbd13-michael MegaDork
5/2/22 2:30 p.m.

I actually havea 2.7x (i think) centersection here. No axles, no limited slip. I also know nothing about floaters or regearing or any of that, nor the cost involved. 

The 8.8 i van grab geared right, right width out of the box for 150. With trac lock. Roy can redrill the axles for free, then i adapt the stock car stuff over. Should be in for around 200, but it sound like the offset pinion may or may not be a bad thing. Its also a lot of work....

Stampie
Stampie GRM+ Memberand MegaDork
5/2/22 3:00 p.m.

In reply to Dusterbd13-michael :

Yeah but then you couldn't look the other drivers in the eye and tell them that you have a 9 inch.

wawazat
wawazat SuperDork
5/2/22 3:04 p.m.

Stay with the 9" Michael.  Buy a complete center section geared, splined (28 and 31 spline are available OEM, 33 and up are HP aftermarket) to match your axles.  That 58.5" width is common to late 60's Mustang/Cougar IIRC.  I sold an entire 9" out of my Cougar for $275 (28 spline, open, 2.79, leaky wheel cylinders and axles seals) after I bought a complete '69 Mustang housing with 31 spline OEM axles for $200. Found an OEM N case 3.70, 31 spline with Auburn diff used and had it checked and resealed.  

Ford 9" came from factory with ratios from 2.47 to 4.86:1 and aftermarket goes way higher numerically than that now.  Used NASCAR parts places have 9" diffs for sale and every parts shop has a variety of bits, gears, and bobs for them.  

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
5/2/22 4:23 p.m.

The driveshaft doesn't care which plane it gets its angle.  It just makes it a little tougher to measure your angles when you're not referencing a concrete floor.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
5/2/22 7:07 p.m.

Are you sure it is offset by 3"?

If it is, when you cut the ends off to put Ford 9" bearing ends on so you are not suffering with C clip axle retention and bearings that ride directly on the axle shaft, you can fudge one side longer and one side shorter...

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