Tom Urani

I have a 1986 Corvette with a 383 stroker motor. The engine is overwhelming my 4+3 and I'd like to replace it with a ZF 6 speed. I understand there may be some tunnel modifications necessary and that the clutch master and slave are tricky. Comments please.

JLeatherman

I've got a 383 and I looked into the ZF swap for my 4+3, but didn't go through with it. You'll need the bellhousing, clutch slave, flywheel, clutch, trans, etc. There is some tunnel modification cause the shifter bolts to the trans instead of to the car like the 4+3. Personally, after reading the difficulties involved I decided I would wait and try one of the bolt-in kits. I'm waiting for my 4+3 to give out and I'm getting a Keisler kit. It's $3600, which puts it about a grand more than a ZF conversion, but I believe it's a better trans and I know it's a better clutch setup. The guys with the ZF clutch aren't happy until they get the McLeod twin disc setup. Also, try getting a ZF rebuilt for a reasonable price. Keisler internals are easily available and not too expensive. Whatever you think is best, but for me I'm getting a Keisler sometime.

Dominic Sorresso

Tom,

Myself and Central Coaster have both done ZF-6 TRANS-plants. Along with the C5 brake upgrade, its the best mod I ever did on my Xfire. ZFs have gotten cheaper recently. Even if you went with the Keisler, you'd still need to cut trans tunnel and glass in the 1989+ tunnel. Not hard to do really. You'll replace the master and slave cylinders, but if you ever replaced them before you'll know what to do. I used the later style and the steel braided line. Since I was down there I used the Fidanza AL FW for the retro fit. You'll love what it does for spinning up the motor.
While you're at it, install the Hurst shifter with the trans out of the car.

LD85

SurfnSun

Keisler had promised a 6 speed swap for C4s more than a year ago and never came thru with it. Id go ZF swap personally.

CentralCoaster

ZF6 conversion cost me $1500 (and some headaches) but I have the parts list all sorted out now. This was with a used transmission $800, bellhousing, driveshaft, and clutch hose. All the clutch parts were new.

A new ZF goes for about $1600 now, so that puts you at about $2300. Obviously, it's more work sourcing parts from a few different places, but that's why the Keisler costs more.






I also cut a little off the C-beam too, it was just way too tight to get back in place beside the trans.

Absolutely do the Hurst shifter at the same time and it will feel like a whole new car, it'll be much easier with the trans out.

Fatt Vette

I just finished mine up a few months ago, not really difficult, just time consuming. ACI Fiberglass makes a really neat product called the ZF6 conversion panel (P/N: ATC 010), makes short work of the tunnel repair.

CentralCoaster

I opted for a $6 handicap parking sign. Perfect size, and relatively thick sheet aluminum.

Plus if the car ever falls on me, I can lay there and look at the handicap sign while contemplating spending the rest of my life in a wheelchair.

dadsC4

Sounds like you guys have it figured out for the 4+3 to the ZF. Does anyone know what I am getting into swapping my 700r4 in an '86 to the ZF from a '94?

bogus

I asked them that... the fitment was just too much of a problem.

rj8806

That's true. Even with a 5 speed there is some modification necessary. Since a 6 speed is physically larger than the 5 speed box, you have to cut even more. We don't know too many Vette owners willing to cut for the 5 speed let alone a 6 speed.

Richard

AKS Racing

Same dance, just a few added moves.

Requires the pedal and cage from a std car. You will also need some parts from a donor car (i.e. console parts, tunnel panel, positive battery cable, late model small starter for the early autos, pilot bearing, dust shield, fw, bellhousing, etc).

And lest we not forget that the D36 is just waiting for an opportune time to part company.

Aaron

Dominic Sorresso

Amen to that. Not gonna be cheap.