Hello everyone I'm a 17 year-old from Ohio with a dream and I was hoping all of you may help me with such a dream. I'm looking to put a 6-speed ZF transmission in a 1989 Firebird. I would like to know if any of you have any experience with such a venture and if so I would appreciate your input. Please only positive reinforcment and no bashing on my luticrous idea. Please any help at all, suggestions would be appreciated. Thank you all in advance.

Sincerely,
Gregory J. Miles

 

see macewn motor sports techlink http://members.aol.com/macewen1 for complete instructions and parts list for t56 conversions

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3.8 turbo 20th anniversary transam #497 first owed by Clifford Williams, Bass player from rock band AC/DC

 

sorry about link its http://members.aol.com/rmacewen1

 

Check the archives, I think the guys nickname is ZBRA. He just installed a ZF-6 not to long ago. I think the biggest problem you might run into is the finding a bellhousing. At the time I was considering this I found a ZF-6 for $600 but I think it was SLP that made the bellhousing adapter and had stopped production on it. So I gave up the idea and found a T-56 for the same cost.

Someone on this this board has done the swap though...

HTH

 

Hey, thanks for your input on the ZF, I'm now considering a T56. How long and painstaking was the T56 swap and how costly. Any help would be appreciated.

Thanks,
Gregory J.

 

there is an article in the tech section or on steve spohns website on the t-56 transmission swap, check it out it is pretty good, also from what i have heard it is a pretty simple replacement for a t-5 so if your car already has a manual it will be pretty easy, however u will have to either fabricate a crossmember or buy one. and u have to trim the tans tunnel shifter opening a little i have heard that it is a fairly simple swap , and im planning on doing it pretty soon

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87 IROC-z 305 TPI 5spd Borg warner 9-bolt 3.45 posi 4 wheel disc,8.8 Accel wires , bosch platinum +4 plugs,gutted air box,k&n oil filter,synthetic oil 10w30

 

I have done the ZF6 swap.

There are quite a few problems with this swap, and a T56 swap would be much easier. If all you desire is to have a six speed, then put a T56 in. You will have no performance gain from the ZF over the T56 since all of the gear ratios are almost identical. While not as "bulletproof" as a ZF, the T56 is strong enough to handle any reasonable amount of power.

With that said, here is the information that I can give you on the swap:

1) Bellhousing. If you can find the SLP bellhousing that was used on the Firehawk, buy it! Even if it is $500, buy it! With it, you can use a regular small block flywheel, and a T5 slave cylinder, master cylinder, clutch disc, and pressure plate. If you can't find one, then you will have to find a bellhousing from an '89 Corvette. It must be an '89. '90 and later used a Magnesium unit where '89 was the only year for the Aluminum bellhousing. You will then need to cut off where the slave cylinder bolts and relocate it lower to clear the floorpan of the car. I hope you can weld aluminum. You will then need the Corvette dual mass flywheel and ZF clutch components.

2) Torque arm. The F-body uses a torque arm to make the firm mounted transmission keep the rear end straight. The Corvette uses a driveline support beam to support the rear of the transmission with the firm mounted rear end. Exact opposites. You will have to get the torque arm off of the transmission. Here is what I used: http://www.jegs.com/cgi-bin/ncommerc...%202187%202188 It relocates the torque arm to the underside of the transmission tunnel. Get ready to strip the inside of the car, carpet, seats, and all.

3) Driveshaft. The ZF uses a larger yoke then a T56/700R4/T5/TH350/200R4/etc... You will need a yoke from a ZF equipped 'Vette. This will not fit on you steel driveshaft, but it fits perfect on the 1LE aluminum shaft.

4) Transmission mount. Like stated above, the 'Vette doesn't have a transmission mount, nor does it have a provision for one. I fabricated a plate that bolted where the driveline support beam goes and ran under the output shaft. I then bolted a regular rubber mount to it. Due to the relocation of the torque arm, I no longer needed a poly mount. The "adapter" plate will need to drop "step" down to clear the speed sensor.

5) Crossmember. Fabricate one. I used a SPD T56 crossmember, and I modified it to work.

6) Speedometer. All ZF equipped 'Vettes had 3.45 gears. Unless you are running 3.42s, you speedometer will be wrong. LPE offers speedo correction gears for the ZF. They run $150 for the set.

7) Transmission tunnel. You will have to cut out a huge section of the floorboard since the ZF is much larger than the T56/T5/700R4. The top half of the transmission will be in the car. You will then need to refabricate the floor pan over the transmission.

8) Shifter. The ZF's shifter sits to the left of the output shaft instead of centered with it. This will create problems with the console. Do some more fabrication.

There will be plenty of other small things that you will run into along the way.

Have you now decided to go with a T56???

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'91 Z28 Blue/Silver ZZ4/ZF6
335.9 RWHP 374.9 RWTQ

 

I'm gonna guess that you gave up on the ZF idea?