dizwiz24

Ive seen people do it both ways...
Typically the pre zf6 guys (ie. 88 and earlier 4+3) do t56 6spd with their lsx swaps

Later cars, that had zf6 as the manual trNsmission use thAt with their lsx swap

Is it generally just availability (ie. If you already have a zf6 sitting Around then you use it) or is one transmission better than the other (ex. Smoother shifting, lighter weight, can handle more hp)?

As diehard of an lt1 sbc guy as i am, i am toying with the idea of an lsx swap in the future.

TLS_Addict

I have had both. I think the ZF shifts smoother but the T56 isn't too bad either.

I think the reason guys go for the T56 is price to build and repair and generally cheaper to purchase. T56 takes some tunnel work to get to fit along with some gabbing up the tailshaft as a mounting point.

No wrong answer but I prefer the ZF.

1985 Corvette

ZF is probably the transmission of choice for those that already have one. The T56 seems to be the go to transmission for those starting at square one. Although I went ZF, I would say the T56 is the way to go. Lots and lots of choices and a DIY build isn't taboo like the ZF. There's so much implied mysticism and "gotta hold your mouth open just the right way when doing every step" talk about the ZF inner workings, it's like yanking your D44 and throwing it on the shop bench for a rebuild: you just don't do it, you send it to a professional. The ZF is fantastic but it's $$$.

383tpimachine

T56 here. Went from a 700r4. Sending it in for a GForce 1200hp build since 4th is shot (Had ~500tq). Better selection of clutches, shifters, and following.

STEVEN13

No way! Are you sure this is Dizwiz and not some LSx crazy person.

cv67

Think the LSx Witnesses showed up at dizwiz' front door and cast a spell on him


Have had both trans also, stock for stock the ZF is stronger hands down but if a built T56 is available dont rule it out (guess it comes down to money). Scattershield a definite if hes going to put down big power billet FW always a plus opinions may vary though.
Smoothness its a tossup depends on the shifter

Lots of options to make huge power and larger CI LSx out there now. Wont be cheap but in comparison cant compare with the Gen 1 sbc
If I had the coin Id do an SB2.2 parts are getting cheaper those things are absolute monsters

dizwiz24

I know. Either motor will make so much power wih forced induction that you wont be able to get traction.

The issue is cost and rebuilding quality.

Ive heard so many horror stories here about bad sbc rebuilds. Its a real risk to spend thousands to rebuild an old platform, install it 9 months later, and then have problems.

Everyone is doing lsx stuff now and if thats what rebuilders understand then....

The parts are cheaper too as there is more competition for lsx performance part s.

I still think a boosted sbc 2.2 with sheet metal intake is going to get provide 98% of the power that a similarly boosted lsx is going to provide. But then traction is the issue...so....

TLS_Addict

I have had two LT1 engines, two LS1's and two LS3's. All great but completely different driving experiences. None are bad.

dizwiz24

Any updates on doing ls swaps with the zf6?

ive found conflicting posts, some saying its so hard to get it right

Others say you can take a 6.0 ls swap (are they all the same), put a quick time bellhousing on it, and a specific push style clutch kit - and its good to go

AZSP33D

Contact ZF DOC for options using a ZF. QT Bellhousing or Billet Adapter, engine mounts, input shaft, etc.

WVZR-1

That might work for some but I doubt for 'most'! I've reached out a couple times regarding the LS/LT5 trans projects. I've got a couple trans and interest BUT I can't get him to respond to emails. I understand busy but he was the one that mentioned the LS projects. I guess he's maybe lost interest.

dizwiz24

no he is still doing work, esp, rebuilding and optimizing zf6 transmissions !

if you guys wonder what im up to, i have a major forced induction rebuild planned with aftermarket engine management. Hoping for +800 rwhp e85. Ill use nitrous if i have to also

im trying to plan and decide ‘what ‘ to do
for the short block

a rebuild of the lt1 (splayed main, factory block) would be simplest with a crap ton of boost thrown thru it
Wish i could find the discont’d afr 227 comp ported head

ive got a black tag zf6 and mcleaod street twin clutch ready to install


im also asking questions about lsx swap, that said im worried about fabricating custom parts and dont want the car to be down for a year or more due to machine shop delays and working out the bugs inherent with an ls swap. I can weld and drill stuff but dont own a machine shop and the machine shops have been b1tches to work with lately (they whine they dont have enough people working). Basically your parts and plans sit there for months until you get pissed off and come take the parts back when you realize they arent ever going to get to it

machine shop i used to use owner /founder Frank was 92 yrs old. Rickety, shaky, but friendly and sharp as a tack. Would crank out parts the same day or same week at worst. Showed up, no Frank. Asked for
Frank and they said ‘he died’. Was confused bc last month Frank was cranking out parts for me. The people managing the shop now stink, they arent the caliber as ‘Frank’

I may try to find a c4 coupe, cheap, missing engine and trans that i can put my current engine and blue tag trans in / once i get a new splayed main lt1 rebuilt (or ls swap)

Phobos84

One thing to consider is getting a new Tremec Magnum-F for an F-body. They are already designed for torque arm so the cars C beam could pretty easily be modified to work. They hold more power than a junkyard T56. And you have a choice of gear ratios. It's not a cheap option at $3500. But I've seen guys spend the same money on a "built" 700R4 before so there's that.

s346k

that is the trans i went with. sold the black tag zf6 3 days after it came out of the car. i'm not doing an lsx engine, but it's all the same behind the crank.

i went with the magnum f because there are already adapters for c beam to tailshaft, clutch options (mcleod rxt twin), im using a quicktime sfi bellhousing, and t56 shifter options (mgw). mgw now has offset shifter handles, whichever way you need them.

i think a zf6 is ok for someone who doesn't beat on their car and plan on breaking anything. for everyone else, go t56.

dizwiz24

good to know thats an option too, but i already have a 17k mile zf black tag ready to install

Krusty84

I would go with a Tremec as there are a ton of shops that work on them and you can upgrade with face plating.
The direction you are going, I would leave room for further upgrades. Face plate, strain gauge... etc.

Are you dead set on a double overdrive trans? Or would a 5 speed like a TKO/TKX suffice? The TKO/TKX transmissions are lighter weight and Silver Sport Transmission has some pretty beefy C-beam mounts for them.

AZSP33D

I think that’s a great recommendation if you stay under 600hp although it installed on the Speedway twin turbo LS C4 project car… low cost, low weight, high quality, I have one but I haven’t installed yet. The SST kit includes a nice shifter option that’s far back and to the left, perfectly centered on the 1989+ C4 manual tunnel.

yakmastermax

Woah man are you doing a SIlver Sport TKX swap into an 89?

Their kit is marketed only for 84-88

How are you making it work?

Super interested in the swap actually.

AZSP33D

It's really truly a no-brainer with regard to that, works perfect, SST 84-88 MT kit is a good way to go. Easier compared to adapting a T56, easier than a ZF swap into a non-ZF C4 (I've done that also).

I think the way they put kits together is a "direct fit" or "EZ fit", meaning all inclusive and you use the early C4 clutch, bellhousing, starter, exhaust, driveshaft (they provide a slip yoke)... you actually need some of those for the 1989+ manual, LS, need even more for automatics (pedals, master slave, driveshaft, maybe C beam). Summit racing sells the SST kits and you don't get so much of the extra stuff like shifter handles, speedo conversion box, patch plate, so if you have the SCCA member discount (10%) you can get it a little cheaper maybe and not have to talk to the "it wont work" guys at SST.

In summary, it's a little more complex but doesn't have to be, especially for the 1989 manual. You can find an L98 86-88 spec clutch and bellhousing etc... so those things you have to figure it out without their step by step instruction, and so it's not a direct fit anymore.

But they may tell you, and told me directly something along the lines of "we don't have any kits for those, there isn't enough of a market for these low budget C4 owners"

You can easily pick up a TKX by hand... picking up a ZF6 is like strong man competition stuff, I'm out, LOL

I keep good records, here's my shopping list... it's for SBC not an LS however:

Tremec TKX #TCET17805 GM 1 1/8" 26 Spline -- 31-spline output shaft -- 600FTLB -- 1st:2.87, 2nd:1.89, 3rd:1.28, 4th:1.00, 5th:0.68, Rev:2.56
SilverSport #EFKC4TKX kit for C4 Corvette
SilverSport #SLA-00505B shifter
QuickTime Bellhousing #RM-6010
ARP Pro Series Flywheel Bolts #200-2802
ARP Bellhousing Bolt Kits #129-0902
McLeod RST Street Twin Clutch Kit #6913-07
McLeod Steel Flywheel #460320
McLeod Hydraulic Throwout Bearing #1350