Hello there,i have completed the 302 ford swap in my 88 convertible,tied up the frame and rein forced the k member up front. now that i have a motor with big power to drop in i am obviously going to upgrade the diff. I have heard of a lincoln 8.8(independant rear diff)and mazda 929 axles mating to an rx-7. does anybody have any info on this swap??

 

Not too many engine swap guys check out the newbie section so you may want to search and read through threads on diff conversions in the Other Engine forum:

https://www.rx7club.com/other-engine-conversions-non-v-8-118/

I remember reading that some people use the Cobra diff but no idea on axles and such.

 

TII differential. Bolts right in with the TII half shafts.

 

+1
you can't beat the TII rear for a easy to slap in Diff.

 

What are its benifits over the stock diff?

 

The stock Diff is N/A,so it is not capable of power over say 250-300.You would end up breaking something,
The TII diff is basically the same sort of design But Beefier and will allow you to run the V8 power but yet keep the stock mounting and it is just "Plug and play" sort of thing on the *** end.
TII diff,half shafts,and a conversion shaft from the 302 Trans to the TII diff is a lot easier than making another Rear end fit in.

 

It won't break like the weaker NA differential and bolts right in, instead of having to deal with the hassle of installing some other random (and likely weaker) diff from another vehicle.

The drivetrain of the TII RX-7 is very strong and will have no problems holding up to the typical 302. Isn't that the engine from the Mustang that puts out sub 200HP in stock form? I'm not up on my iron block V8s...

 

Yeahup right now the car is seeing 330 rwhp and I have a 275-40-17 in the rear. Just waiting for it to blow. Anyone know the ratios in the turbo 2 diff? And the n/ a diff? .and is the driveshaft the same from the diff yoke?

 

330RWHP will be no problem for the TII stuff.

Here's a list of all RX-7 final drive ratios: http://www.mazdatrix.com/g5.htm

The driveshaft is different but since I figured you have a custom driveshaft anyway, the flange can be swapped.

You'll need the differential itself (preferably the S4 clutch type LSD) and the two axle shafts. While you are in there, weld up the mounting flange on the subframe (they break) and replace the rubber mounts on the diff with the Mazda competition style.

 

Well that's awesome thanks for the help. I knew it was a 4:10 gear in there. I'm gonna do the swap as soon as I can find a diff. I wish they made a 3:73 ratio. Any aftermarket gears available?