Rear end upgrades, and axles?
 

So I have been playing around with using an SA rear end in my build because of its factory width. It's only a couple inches longer than my factory rear end.
But I had a serious "duh" moment. I was under the impression that they were a 4x100 bolt pattern. It's not.. lol
Secondly I thought this rear end was an LSD. Again, it's not.

So my questions go like this..
I'm looking for info on people that have redrilled they're hubs to a 4x100 bolt pattern. I was thinking about a disc brake upgrade to go with that. But drums would get me by.
I'm also curious about LSD's. Will an LSD from a later model work in this diff? I have some 4.30 gears coming from a miata, and a nice set of 4x100 wheels. So I don't want to give up on this project, and build a differet rear end..
Anyone have some advice for me??

not sure the overall length of the 79-80 rear end hub to hub, but my thinking is that since it uses the small axle shafts/bearings u may be able to swap in the diff from an 81-83 gsl and retain the SA drum brakes. i don't know how much is interchangeable between the SA and early FB but u may also be able to use the axle shafts from the early gsl as well and gain disc brakes. but then u would also need the master cyl and proportioning valve from the gsl.

Well what I was kinda thinking about is an aftermarket axle that's drilled to 4x100. Then maybe making a custom bracket to use miata rear disc's, and calipers.
This is all going into a 78' Datsun wagon. So I'm trying to source cheap parts, and save money to put elsewhere.

I might have a lead on a FB part out, if I'm right they all had LSD rear ends? Which would save me a bit of hassle.
But I'm not sure??

All of these options have been covered throughout the last 40yrs.

1. What power are you going for?
2. Would you consider modifying the body to allow for superior, modern geometry?
3. What's your budget?
4. Is 4x100 really critical?
5. How critical are you with weight? There are cheaper/heavier options out there or more expensive/lighter options out there.

Could the later series 3 rear end fit under the 510? They have disc brakes. the axles and bearings are stronger and the 84-85 GSL has a decent clutch type LSD. Moser sells upgraded axles you could get in any bolt pattern or re drill for 4x100 easily. That may be the cheapest route to go for now

As I recall, the disc brake rear ends have LSDs. I don't know of anyone doing aftermarket axles for these rear ends any more - I know Moser did at one point but if they still bother... no idea. As long as you're not hung up on hubcentric vs lugcentric stuff, redrilling the axles is pretty easy.

S3 rear axles have a different spline on the differential that's shared with the Miata which means the Miata torsens fit and also all the other aftermarket Miata diff stuff.

You can use 79-83 rear ends the only difference is the driveshaft mounts are different mid 83 and some of the years came with LSDs in them and disc brakes. You probably want to look for the a GSL rear end that has an LSD and disc brakes. Then you can go about redrilling for the 4x100 stuff. Would be easier than doing it for a drum setup I would think.

1. About 200hp.
2. No. I was gonna keep the leaf springs, and run caltracs.
3. My budget is low right now. Around $400.
4. Yes I already have wheels in that pattern.
5. The car will be around 2200lbs more, or less. I'm not terribly concerned with weight. My other option would be a Toyota 8 inch, or Ford 8.8. But I don't really have the money to build one right now. I want to try and work with what I have.
I believe that the FB rear end is the same width as the SA. But the GSL-SE rear end is a bit wider I think? I'm not sure though??
I did find one close by, but the price was ridiculous!
So only the newer (83+) diffs shared the same parts with the miata junk. But the crown, and pinion are still the same threw out the years right???

I guess I should keep hunting then. There's a strong majority for the series 3 diffs.. lol

GSL is not the same as GSL-SE and should be way cheaper. I would hold out on the Series 3 rear end I think you could find one under $400 easy

I will do..

Thank you for the info, and feedback everyone.
Its appreciated. :icon_tup:

Correct.

Alex wrote about this in Post #2. The 84-85 GSL is the best option, followed by 81-83 GSL (larger teeth, smaller bearing), then GSL-SE (weaker LSD).

http://*************.com/rotary_foru...ead.php?t=4323

I have a Toyota 7.5" Axle Housing for sale if you want something in between.

Definitely check out Weir Performance. I have their goodies in my Toyota 8" Solid Axle setup w/ MKIII Supra 1.5 Way LSD.