Just looking for some info and opinions… I plan to eventually install a GMPP ZZ4 under the hood, and I fully realize from what I’m told, that the tranny (BW T-5) and the rear end (3.73:1 Open) won’t hold up. I’d like to go to a T-56 six speed from a 94-97 F-body, and I’m clueless about what rear to get.

Right now, the L69 runs great, and I plan to keep it for a while longer, and swap that into another car when I get the ZZ4. One of the things I don’t know about is the tranny swap. I don’t have a hydraulically assisted clutch. I have the old style linkage. Will this bolt up to the T-56? Yes I did a search on this, but no one I’ve read about did this swap with a manual linkage. Heck, I’d be willing to switch to a 4 speed if it was an easier swap, and could handle the power. I don’t plan on much highway driving anyway.

So far as the rear goes – I’m looking for something strong enough with a posi and 3.43:1 ratio but nothing lower than what I have right now.

So- if any of you gearheads have opinions and info on which way to go with this, I’d appreciate it.

 

no the mechanical linkage wont bolt up

even if you had hydraulics, you would still need to upgrade to T56 hydraulics


cant really recomend a rear cuz 12 bolts for these cars are $2000

 

AFAIK there's no way to use the old mechanical linkage with a stock T-56.... you'll have to swap in the hydraulics.

They still used the same old 7½" 10-bolt in 4th gens, right up to the end of production. I think you can treat it halfway reasonably and get by with it.

I have the rear out of a 91 or 92 GTA, stock axles (yuck), an Auburn Pro posi, 3.73 gears, and the PBR rear disk brakes in my 83; it has the axle tubes welded up and a stud girdle cover, and a crush sleeve eliminator; seemed to hold up OK to the 400 I had in it for a while.

 

Thnx for the input guys. Honestly, I was prepared to spend around 1800 bucks for the rear, and most likely the same amount on the tranny.

I do plan on thrashing a bit at the track, and I don't want to break down. I've always wanted a car that will pull the front wheels off the ground, get serious traction, and run 11's or 12's - all motor. I realize It'll cost some bucks to do it, but I'm not gettin any younger. This is my "toy", and I don't depend on it to get to work.

RB83 - I appreciate the advice you've given me (and others) since I started frequenting this board. Just thought I'd toss that in.

I've read posts from a few that they swapped to a 4th gen rear, but they're too wide. What do you do in that case? Get wheels with a certain backspace or what? I like the idea of swapping to a 4th gen posi unit - if I can get it to fit and not look too funky.

1991tealRSt-topGuy: I was hoping I wouldn't have to swap to hydraulics, cause I'd be willing to bet that my car won't have "indentions" on the firewall where the optional slave cylinder is supposed to mount. Guess I'll have to "wing it" once again. Would you recommend a factory T-56, or a Richmond aftermarket? Which swap is both easier and will be stronger in your opinion?

I'm not gonna lie and say that money is no object - but I want to get the most "bang" for my bucks.

My final goal in the end, is to have a car that is streetable, fun, and will lay down some decent times at the track.

What I have now is fun to drive, but I'm afraid to pound on it too hard cause I know either the tranny or rear won't last.

 

You can use 4th gen rear wheels to fit with a 4th gen rear.

There's no point in swapping to a 4th gen rear. It's exactly the same as what you've got, in terms of strength. No difference whatsoever, except that it has the 90-up larger axles. You can get a 90-92 rear and use your stock wheels, use a 4th gen posi in it if you want to, since it bolts right in (it's the same rear end, after all).

It's not difficult at all to do the hydraulic swap. I've already done it to my 83 car. It actually goes in the same place in the firewall where the linkage goes through; the hole just has to be enlarged a bit in the downward direction, and 2 smaller holes drilled for the bolts. It's really not very hard to do at all.