Automatic Transmission 968 Conversion

I just bought a 968 Cabriolet with Automatic Transmission. I am planning on using the engine in a race car and am investigating using the rest of the car for a V8 conversion. I am not looking for a high HP engine, just a nice weekend cruiser. I know that this conversion has been done by stuart f. wright on this forum, but I can't find any of the details.

To get started, I'd like to know how to adapt the flex-plate to the torque tube

I dont think he used a flex plate... He still used the clutch disk and pressure plate, but there is no hydrualic throwout bearing. The engine is constanly engaged with the torque tube. Very easy!

Thanks, I appreciate the information. I continued searching and found his post on this topic.

Hey John welcome to the neighborhood. I've been trying to pull teeth on rennlist about the 968 Torque tube as I have "heard" that the 968 TT can't be used for the V8 swap. I say otherwise. The Auto tube is a complete shaft and the manual has a copler at the BH just like the 5-speed 928. From talking with Eric (admin) he used the 928 flex coupler to LS1 flywheel and I believe the same could be done for the 968 auto. Maybe he will chime in and shed some light.

I swear I haven't figured out how to post a link from frenemylist.....

>>>>>>Post what you know about the 968 TT. The Ebay pics state that TT is from a 6-speed manual and the drawing posts a part#, but doesn't state what it's from on Pelican. As you can see the drawing has a solid extended shaft and the Ebay pics have the shaft cut off right at the flange (I'm assuming 968 TT is just like the 928 TT design).....>>>>>

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If you right click on the link on rennlist, then do "open in new tab" or "copy link" it will give you the address to the thread.

I don't know why you don't like rennlist...i'm sure at one point they hated the v8 conversions, but now just about everyone on there seems fine with the conversions.

Unfortunately, I don't know anything about the automatic torque tube. The only area of concern is in the front where the bellhousing bolts on. Knowing Porsche's history of re-using parts on different models, I'm hoping its the same as the manual. Whether either of them can be used for a V8 conversion is the bigger question. Re the Ebay picture it looks as if the shaft is just pushed back into the torque tube.

Thanks, for the information. If I read it correctly, It looks as if the Auto 968 torque tube will bolt up since its the same as the 944.

Correct, and the 968 flex plate copler has to be modded onto the LS flywheel somehow.

Another missing piece to the puzzle.....

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the way i see the picture of the 968 tourqe it looks the same as the 944 auto.the auto tube in the 944 is virtualy the same as the manual tube where the spines are concerned.it has the same distance as the manual where it slides into the splines.once you have your old motor out you should be able to mesure.i did mine the same as the members with manual conversions except i didnt put in a throwout bearing even though you could and have an clutch auto like the old b n m hydro sticks. if you go to members conversion area you will find mine with detailed description of my conversion

Stewart, Thanks, I'll take a look at it. Can anyone tell me if A/C can be installed with an LT1 engine?

and i might add the coupling device pictured hooks the splines to the rubber lined flexplate on the porsche motor.you wont need it all you need is adapter plate for 2 piece bellhousing flywheel presure plate and 23 spline mopar clutch disk.one other thing on an late model lt1 uses a totaly different flywheel than i used as i have an early sbc chevy in mine.the lt1 uses an externaly balanced flywheel .and yes you can hook up ac to an lt1 in your conversion.and also it is my understanding that the 944 and 928 are different and the 968 is close to the same as the 944 with cosmetic differences but the drivetrain is very simular with the exception that the auto in the 968 is a 4 speed and the 944 is a 3speed.in the front of the tourqe tube that goes to the engine should be the same.ive seen pictures of the 968 tt and it looks very simular to the 944.

Although that works, you're adding quite a bit of unneccesary rotational mass to the driveline. I would bet that the 968 Flex coupler can be modded to bolt to the LS auto flywheel and call it a day.

Most definetly A/C can be used on an LT1. Use the F-Body brackets. Small frame rail massaging required by very minimal.

i bet some of your expert machinist skills could make something to tackle the auto conversion xshop.where was you 10 years ago.lol. my auto conversion seems to work really good with a clutch setup and was very simple to install compared to the first time i did my conversion where i accualy used a flexplate with the coupler.then i noticed while installing a new motor some weakness on my coupler and did some mesuring and decided to go with clutch style hookup.i like stick shift cars but this thing is a screamer with an auto and like a bullet off the line and i havnt had any problems out of the tranny.ive seen and read about alot of the stck shift cars with broken gears ect.i also know the 968 auto can hold 450 ft lbs of tourqe.

From all the info I've gathered we don't have to look any further than the 928 Auto Flex plate coupler for the 944 Auto and 968 Auto Torque Tube swap.
Mate it to the LS flex plate and make a pilot bearing adapter accordingly....

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I've got to say that this forum is fantastic. A whole lot of very useful answers in a short period of time. Thanks to all. My 968 (bought on Ebay) is still in frozen Iowa awaiting pick up by an auto transporter. It had some water damage and resulting electrical issues, but it only has about 30K miles on it. It appears to have some cosmetic issues but nothing major. I have a used engine harness that should hopefully get it running again. Once I check out the 968 engine and transmission, I'll pull the engine and start the conversion.

I would like to keep the conversion as simple and inexpensive as possible, but several items are important to me:

A/C I live in South Carolina, enough said.
Power Steering
Power brakes

I know that I have to decide between an LT1 and LS1 and could use some advice. I think I will be happy with around 300 hp given the car's likely role as a weekend cruiser.

I assume that the GM power Steering pump can be mated to the 944 rack.

I will stick with the stock suspension, but may upgrade to the M030 front brakes, since I have a set of front calipers and spindles. Advice on the GM hydroboost or other alternatives appreciated.

I owned an early 944 with a SBC, and while it was fun for short outings, the handling and braking were scary at best.

I looked at the flex plate adapter. It requires a cross bolt. I'm not sure if it will be accessible through the GM bellhousing. I guess I could always drill a hole or tighten it to a slip fit and weld it closed.

I believe Camaro and Firebird engines have the best accessory locations for the conversion. Is that true on both LT1 and LS1 engines? if not, what is the best choice for each type?

2 piece bellhousing would give easy acess to the cross bolt

Sounds like a plan

Either way there will be a solution for running the 968 Torque Tube.

eric at texas performance concepts recently converted a 928 auto and he has some insight to the therory of using an ls style auto flexplate on your conversion or you could do like i did and just use a clutch style conection to the engine.but either way will work .as for engine selection the new ls3 motors are really badass motors.would really make a good one for your conversion.i have one in my 2011 camaro ss and it is a very powerful motor.

There is another dimension that needs to be confirmed on the 968 TT.....
The diagram is confusing, but on the TT's there is a larger initial indexing diameter that tapers to the smaller I.D. of 3.031" (which is what the C5 adapter plate indexing spud is machined at and centers the TT shaft)......

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