aelli614 None
Jan. 1, 2015 6:08 p.m.

So I'm going to be doing a enginf and transmisson swap in my spit. Ive come to learn that the diff will also have to go. So from what I've read I see the r160 is the way to go. The mouting plate is goning to be made locally for me. My question is with the axles. The r160 I know has to be the type with fixed stub axles.

Now from what I gather I need to use the half shalfs from a old 240z/510s. Is there anything else I'm missing?


spitfirebill PowerDork
Jan. 1, 2015 6:54 p.m.

This interests me greatly. Keep us posted. I was thinking the diff you wanted was from the 510. Getting hard to find now.

erohslc Dork
Jan. 1, 2015 7:32 p.m.

Here's a long running thread that you may find useful:,720316,page=10

Post #136 describes a Group Buy (closing January 12, NFI etc.)

The 'rear plate' is very rare, basically unobtanium, some folks have searched for years to find a raw
casting, then are faced with finding someone to do the machining.

The 510 diff uses stub axles with UJoint flanges similar to Spitfire.
Later Subaru R160 used stub axles that mated to CV tulips, while recent Subie use regular CV having an integral stub axle on the tulip.

There are a lot of variations of axles, ratio, LSD, so choose wisely.

DLD New Reader
Feb. 2, 2015 11:44 p.m.

We are building a 64 spitfire and using Toyota Supra Mk3 LSD. We got a 91 turbo roller for $150.00 that had an engine fire and was pretty well picked over, but still had all the suspension. It's wider, but we're planning on using IFS Toyota 4wd axles (they are much shorter) to keep the width in check. We'll start a build thread here when we get started on the real work. So far we're gathering parts. This is for the $2015 Challenge (or the $2016 if we run out of time). Oh, and the Supra diff has stub axles with a 6 bolt flange to bolt the tulips to, so it can be adapted pretty easily to other axles.

Curmudgeon MegaDork
Feb. 3, 2015 12:46 p.m.

The early R160 diff with the 'bolted in' stub axles are what you seek and no they are not common. The bolt goes all the way through the stub axle and into the diff spider gear. Bolt in spider gear on the left (duh).

I have heard tales whispered late at night around the campfire embers that some Subaru R160 and R180 diffs have this setup too but I have never seen one.

The problem: the Spitfire design swing axles try to 'pull' the stub axles out of the diff and the vast majority of IRS diffs have 'pop in' inner CV's held by a wire snap ring. That means as soon as the axle 'pulls' at the CV it's going to pop right out.

On the Abomination and also on the current GT6 project, I had to add upper and lower control arms so they accept this 'pulling' force. No it ain't easy.

erohslc Dork
Feb. 3, 2015 3:59 p.m.

You still see the Subie R160 with stubs on eBay (that's how I got mine), no 'modern' car builder wants them, so they can be had reasonably.
The Datsun 510 stub axles with bolt-on UJ flanges are the rare birds.

BTW, Datsun 240Z used R180, these are a bit larger and longer, and the NZ cast rear plate does not fit.
Fitting R180 to Spitfire with swing axles requires surgery because the diff axle centerline has to match up to the wheel centerline (else you get toe in/out).

But once you choose to abandon the Spitfire swing axles in favor of an SLA suspension, you no longer have
to worry about exact diff axle centerlines so R180, R200, etc could be mounted a bit forward to clear the Spit frame rear crossmember.

In fact, the original model 240Z had the diff mounted forward, the axles angled back a bit to the wheels.
This proved problematic with the UJ based axles of the day, and in subsequent years they moved the diff backwards to line up.

CV axles don't have such issues, they can easily tolerate axial, radial, and angular misalignment in any plane.

evildky Dork
Feb. 4, 2015 10:15 a.m.

The 240Z did come with the R180 but the half shafts share a bolt pattern with the R160 equipped 510, at least thats how I remember it.

DLD New Reader
Feb. 25, 2015 9:37 p.m.

FYI, I started a build thread for our Spitfire. No real building yet, but some photos of the Supra suspension/diff you might be interested in. Look for it in the build thread area, it's "Another Spitfire Build"

You'll need to log in to post.

Also on Grassroots Motorsports

Grassroots Motorsports Experience Ticket Renewals Have Been Sent

16 hours ago in News

Check your inbox for our Grassroots Motorsports Experience renewals.

First Drive: Turbo ND MX-5

17 hours ago in News

We hit the track with Flyin' Miata's latest power adder.

Project Turbo Miata: Fire Fighting

19 hours ago in Project Cars

We transfer the fire system to our new Miata.

Vintage Views: GMC Syclone and Typhoon

1 day ago in Articles

All-wheel drive, turbo power and a Q-ship’s stealth.

Classic Motorsports Mitty Presented by Hagerty Celebrates Porsche

2 days ago in News

Gearhead heaven? We think it looks something like this.

This Weekend at the Mitty: The Ultimate Auto Festival

5 days ago in News

Gates open this Friday for the Classic Motorsports Mitty at Road Atlanta.

ND Miata Turbo Kits Now Available!

6 days ago in News

Add 70 horsepower and 70 ft.-lbs!

What's the Plan, Man?

6 days ago in Articles

Thoughts on our racing plan for the year.

Meet the Rebels Who Started the Cannonball Run

1 week ago in News

Relive those desperado days through movie excerpts, and hear the real facts and wild stories from the legends themselves.

Up for Auction: All of Level 5 Motorsports's Hardware

1 week ago in News

It's a pro race team part out.

Can You Really Live With a Low-Buck Porsche 911?

1 week ago in News

For the past two years, on of our forum regulars has been chronicling his life with a Porsche 996.

Reader's Ride of the Week: Autocross Abomination

1 week ago in News

Classic British styling with a rotary engine?


Grassroots Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Grassroots Motorsports Magazine!

Learn More