1991 Z28

Has anyone ever swapped a 6-speed transmission from a TPI corvette into their third gen? I was wondering if it would be a direct swap to our TPI engines. I have a 91 Z28 with a 305 TPI and a 5-speed transmission. I wanted to do the T56 swap from a 4th gen but didn't want to do all the crossmember and vehicle speed sensor changes so I was thinking about the 6-speed from the TPI corvette cars. Would I have to change anything? Thanks

sofakingdom

iTrader: (1)

No it is not a direct bolt-up at all. Bolts right up to the motor of course, since both engines are small block Chevy; but doesn't even come close to fitting in the car, in numerous ways.

TPI has nothing to do with why or why not.

The T-56 is a FAR better option.

Twin_Turbo

iTrader: (25)

The ZF6 / S6-40 is HUGE:

Compared to T5:

jmd

iTrader: (4)

Bolt-in? No.

You need a modified one-year only alum. bellhousing or aftermarket scattershield.
The trans. slip yoke needs changed.
The shifter location is more straight forward using an LT1 T56.
If you don't use the sprung-hub dual-mass flywheel, the S6-40 ZF trans. has rattling noise.
If you use an LS1 or aftermarket T56 w/ adapter plate / shim setup, your stock clutch stuff will work but the driveshaft needs shortened.

If you rebuild, parts are double (or more) for the ZF than they are for a T56.

The clutches are about the same cost.

Guest

The '92 Firehawks came with the ZF.
If you have the ZF, try to sell it. They're not quite as strong as most T56s, and they present problems for rebuilding.
But if you're determined to use it, then contact Bruce? at Hawk's Third Gen Parts. I believe he owns the green Firehawk. (All the others were red.)

Bill Chase

Not as strong as a t56? That's not really true. Ever seen a zf break with 500 hp? How many t56 break with less hp? Not arguing but the zf is pretty damn stout.

88IROCvertZ

iTrader: (1)

I love the ZF in my Vette... one of the best manuals I’ve driven.. makes the T-5 look silly...

T56 is a good trans, but I prefer the ZF... whether it’s worth swapping is another question if a T56 will save you $$$

TTOP350

iTrader: (8)

It's a bolt in, IF and I mean IF you have ALL the SLP swap parts.

Bill Chase

Never understood why gm couldnt put a converter under each rear seat and make all gens of f body true dual exhaust. I guess they couldnt have them running as good as their flagship Corvette though.

I've owned an 81 bird. 93 ta. And 87 berlinetta and all gems were the same. On the 93 putting a 3.5 or 4 inch single was doable except for the massive kink by the Pan hard bar bracket. I bet it choked the 3.5 inch pipe down to 2.25" .. interesting it still ran better than it did stock.it was a 93 lt1 with 700r4. First year of 4th gen.

scooter

iTrader: (11)

Re-tooling the floor is expensive, plus it would require new crash testing from what I understand. That's part of the reason GM kept the same floor for the 4th gens, my understanding.

Plus that is really far away for the cats, especially all those years ago

sofakingdom

iTrader: (1)

LOOK AT the pass side front seat floor, then JUST IMAGINE the gas pedal about 3" further up into the dash, the way it would have to be if they raised it enough to run pipes under it. I think you'll figure out right quick why they left the driver's side front seat floor the full depth that it is. Remember also, the Vette has a TOTALLY DIFFERENT "frame" arrangement underneath it, as well.

Big&BadGTA

iTrader: (1)

The ZF6 is a great transmission and the early ones sounds great w/ their straight cut internal gears. I have two Corvettes w/ ZF6 transmissions. One is an early Black Label 1989 car and the other is a blue label car.

I was actually speaking with another friend last night who swapped his DN 4+3 in his 1988 Callaway Corvette to a ZF6 and the larger (wider) transmission required the tunnel to be modified. He had burnt through two OD units on the DN 4+3, but never had any issues w/ the ZF6. The Callaway was rated at 382 hp and 565 lb-ft torque from the factory. The ZF6 is plenty strong. It's also oh, so smooth.