1999 Drivetrain Swap with OBX RX-7 LSD into 1.6l
 

Hi guys,
This is one of my first posts. I am an avid car fan, I started with wrx, have owned ae86, and this is my 2nd miata. The first one i got was a 1995 with 90k miles. I just picked up a 1991 miata with BEGI 4.2 turbo kit. Besides that the car is original including the rear shocks! The transmission has seen better days, but does have a mazdaspeed miata clutch, tho chatters like hell for 5 minutes after starting cold. What is the reason for this? The flywheel needs to be resurfaced?

Anyways, I recently sourced the drivetrain from a 99 parts car, automatic. He is willing to sell me the rear end, the driveshaft, and half shafts for $300 bucks. Of course it is OPEN DIFF :fawk:

I have also sourced a new OBX lsd for 2nd gen rx7, brand new.

As far as what i am reading online, this is a straight forward open the 1.8 diff and put in rx7 lsd, reassemble, and bolt into my 1991. Is this correct? I will change the diff bushings, and diff seals in the meantime.. Anyone have the diff seal part # on hand?

From this website:
http://members.aol.com/solomiata2/RX7LSD.pdf

It says that the rx7 stub shafts are needed to complete this swap? Just wanted to confirm this is correct. Also, since I found a 99 parts car, should I just buy the axles from him as well? Does this make a difference?

I bought the car for $4600. Compression was 175, 175, 160, 175 roughly with about five cranks. The engine seems to be running strong but because the tranny is old and the gears are SO SHORT, I really feel compelled to do this swap. I know this will jump my cost into this car close to 6k dollar range.. and it's still a 91 with 175k miles, tho the turbo is SMOG legal here in california...

Also, I need the 4.1 final gear as 99 was 4.3, should I buy this part from the dealership? Where should I look for this?

Finally, I have found the 94+ transmission for around $250. If I do go ahead with this swap, I will also do the transmission at the same time. The speedo gear from these trannys are set for the 4.1 final drive gear, so the speedo will be accurate right?

I know I am asking a bunch of questions, I did search long and hard, and just want to confirm my findings before I pull the trigger. :bang:

Also, anyone in the San Francisco Bay Area willing to help me with the swap for $$$.

Thanks in advane to all you die hard miata fans!