hey everyone i searched online and tried my best to find some info out on here but no luck so hopefully the thread will bring some light to my question.my freinds have 1st gen rx7 one has a 83 and the other has an 85.one of the said that the previous owner told him that the differential has 3 ratios that can be selected.if anybody can varify this true or false it would be much appriciated

 

There are really just two common rearend ratios for the 1st gen.
The 3.909 that all 12A cars have and the 4.076 that only the GSL-SE has.They can be swapped from and 1st gen to another,but thats all the factory offered.....(theres a small varience in the 3.909 gear ratios,when they changed from coarse to fine tooth gears,but its very,very slight)
There are aftermarket lower gear ratios suitible for racing,that will give you more grunt and torque down low,but they will limit topspeed and accelerate drivetrain wear if used on a daily driver.

 

You can get a 4.87 and a 5.12 from Mazda and though scarce a 4.44 from a truck will work as well.

 

https://www.rx7club.com/showthread.p...t=kia+sportage

here this will get you started

 

thanx for the help everyone much appriciated

 

ok sorry to hijack the thread but i didnt want to start another 1. so please bare with me. i did some searching and i didnt get to find what i want it. heres what i learn over the search. i know tha you could swap the gears from a kia to a GSL-SE differential.right? but can you do the same thing to an 85 GLS differential

 

anybody?

 

the kia and b2600 4x4 gears (same gear and pinion shaft) will fit any pre-86 RX-7 (GSL, GS and GSL-SE) including old school. The only exception is the regular RX-3 (non SP version; not sure on RX-4 and R100) as it came with long pinion shaft; it can be converted also but you need to get a custom driveshaft.

So far, here's my inventory
75 RX-3 = 4.78
73 RX-3 = 4.44 (soon to be turbo baby!!)
84 GSL = 4.44

 

Racing beat has other gear selections as well.