Dusterbd13
Dusterbd13 MegaDork
11/10/17 5:48 p.m.

85-88. 3.90 gears. Clutch type.

For a challenge car.  Gonna stuff it in a v6 miata. 

Im near Charlotte nc. Willing to drive a few hours.

wvumtnbkr
wvumtnbkr UltraDork
11/10/17 9:36 p.m.

That should be 86 through 88.  The 3.90 rear is gonna be from an automatic car.

I think you are gonna be looking for a gxl or vert only rear.  Not super unique, but make sure it is legit before buying.  A lot of them get swapped.

 

A lot of people want the 4.10 rear end instead. You may be able to get a 4.10 and trade someone for the 3.90.

 

The turbo rear end only came with 4.10 gears in the us.

Dusterbd13
Dusterbd13 MegaDork
11/11/17 5:19 a.m.

I wouldn't kick the 4.10s out, but 3.90 would be better due to torque and 3400 rpm range. 

wvumtnbkr
wvumtnbkr UltraDork
11/11/17 5:45 a.m.
Dusterbd13 said:

I wouldn't kick the 4.10s out, but 3.90 would be better due to torque and 3400 rpm range. 

I did a motive force vs speed chart for this engine, trans, and rear end and found that the 4.10 was better with the size tires I run (225 or 245 15s).

 

Lemme see if I can help you track down a rearend.

Dusterbd13
Dusterbd13 MegaDork
11/11/17 5:47 a.m.

We're going to be running 205 50 15 spec Miata Tire. Wider would be better but there's also real money versus challenge money

wvumtnbkr
wvumtnbkr UltraDork
11/11/17 5:48 a.m.

You just need the center, right?

Dusterbd13
Dusterbd13 MegaDork
11/11/17 6:03 a.m.

Far as i know. My understanding is that you swap the hogshead into the miata aluminium housing and its good to go. Like a hogshead swap on a ford 9 inch.

jmabarone
jmabarone New Reader
11/13/17 8:40 a.m.

To put it out there, I have a spare diff for my '83 GSL sitting in my basement.  If it could work for you, I can go dig it out this evening and see what gear it has.  


I was not planning on coming off of it, but I could definitely use the cash money right meow.  

pitbull113
pitbull113 Reader
11/15/17 9:05 p.m.

I'm curious what are you using for a driveshaft? The RX7 chunk is several inches longer than the Miata chunk.

Dusterbd13
Dusterbd13 MegaDork
11/15/17 9:16 p.m.

Im going to be custom building one. Its goin in a miata with a gm v6 swap.

 

Jmabarone: where are you located and what kind of price?

Dusterbd13
Dusterbd13 MegaDork
11/15/17 9:37 p.m.

Unfortunately, has to be an s5. 85-88....

 

Thanks though!

Dusterbd13
Dusterbd13 MegaDork
11/19/17 2:29 p.m.

Anyone?

Have miata parts to trade....

wvumtnbkr
wvumtnbkr UltraDork
11/19/17 3:25 p.m.
Dusterbd13 said:

Unfortunately, has to be an s5. 85-88....

 

Thanks though!

I think you mean 86 through 91.  The s5 are torsen only and the s4 are clutch type.  They fit the same housings afaik.  The clutch type are more desirable. 

 

S4 is 86 through 88.  S5 is 89 through 91.

wvumtnbkr
wvumtnbkr UltraDork
11/19/17 3:31 p.m.

If you want, call or text me....  I can answer questions and we will post them on the thread and include miata info.  1 stop shopping....

 

Seven too fore 858 zero 6 7 five.

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