can an extended shaft be put in and case the differential connection point to move it backwards in the car? im installing in reverse rotation. just would like to get the engine out of the trunk area. pretty sure it can be done, but, really need to know if anyones already done it or tried. Thanks Ron

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Thanks for the help. Ron

HUH? Pumpkin in a Fiero? only at Halloween

Seriously... can you tell us a little more about what you are trying to do and with what engine/tranny?

Thanks

You're dealing with a THM425 or 325, right? I don't know of any documented extensions like you talk about. But I did see pics MANY years ago of a Corvair with that done. About a foot long tubular structure was welded up, and some sort of extender shaft was added to reach form the tranny output to the diferential input.

It can be done, but you're on your own. I would be impressed if you can do it, and I'd love to see it done. Good luck!

quote Originally posted by XMXRACER62: just would like to get the engine out of the trunk area.

Wouldn't that put it into the passenger compartment?

I'm sure it can be done too. Sorry that I don't have a helpful answer.

SORRY YES- I WAS IN A HURRY TO GET OUT THE DOOR WHEN I POSTED. A 3254L 84 ELDO TRANS. IM WORKING ON PUTTING IT IN REVERSE ROTATION, IM GUESSING 7 - 10'' WIL PUT THE MOTOR SQUARE IN THE MOTOR COMP. AND ELIMINATE THE NEED 4 OIL PAN MODS. I HAVENT TORE INTO IT YET- JUST WAITING FOR THE TRANS TO COME IN. A FRIEND OF A FRIEND THING, THE WHOLE CAR FOR 4-500, THAT KIND OF DEAL. OPM SENT ME A FILE THAT WAS GREAT FOR THE ENGINE FORWARD INSTALL, AND WAS INFORMATIVE FOR MINE AS WELL. JUST WONDERED IF ANYONE TRIED AND COULD GIVE SOME INSITE. ANY IDEA WHERE THAT CORVAIR ARTICLE MIGHT BE? I WILL KEEP YOU POSTED CAUSE IF IT WORKS IT WOULD SAVE THE WHOLE TRUNK OF THE FIERO AS WELL. IM BUILDING A 6.0 BY THE WAY. THANKS FOR LISTENING RON

Yes, you can do this. As a matter of fact, it might make fabricating & alignments easier to work with.

Folks reading this might forget that your working with a Lambo rebody, so you have a huge empty space available due to the chassis stretch. You have created a big empty space behind the cockpit firewall and the front of the engine cradle.

I did some dry fit measurements just like this a few years ago. I was usig my LT1, and speculating that I'd flip the differential ( so as to obtain the reverse ) and then I'd space the differential away from the normal mounting flange on the transmission by using a tunnel instead of a plate ( such as the Street Dreams plate ). I was locating the output axle shafts of the differential somewhere below the harmonic balancer of the engine. That got those axles out of the oilpan, into open unobstructed space. And I had plenty of room to go before hitting the cockpit firewall. You have to remember that reversing the 325, and extending the differential mount, moves the engine towards the front of the car. Just what you want.

To complete the "flip/reverse/stretch" I imagined building a tunnel with a mounting flange on each end, one drilled with the normal trans bolt pattern, and one drilled with the flipped bolt pattern. Inside there would essentially be a drive shaft. Working with racing speed shops, you can assemble some type of shaft that will have splined shaft couplers on each end, one male & one female. Best to be real clear on what you want and are doing if you go this route.

Don't forget to make provisions for the internal lubrication of the front bearing of the differential, it comes from the transmission. And your venting of the diff is now a drain, as well.

David Breeze

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Pantera Rebody Kits

If I can get some of my AutoCAD drawings converted to pictures, I can show you a couple things I looked at doing. It was very similar in that it was a reverse rotation 425 and I wanted the axle shaft to be further to the front of the engine/rear of the car to put more weight in front of the axle.

I was planning to disgard the original diff, make a plate to cap off the end of the tranny. Then use an output flange to transmit the power to a rear diff. On the 425 the splined axle flange from the short side of the diff would slide right over the stub shaft coming out of the tranny, so I had planned on using it for the output flange. Then I would use a reverse rotation front diff from a 4x4 at the rear and either directly couple to or use a small drive shaft. I had a toyota 4 runner front diff mocked up and it fit very well, but it had a 4.10 ratio or higher... not the best for a 3 speed auto, but could be fun with the 4 speed auto version.

OK- SO WHAT LITTLE ROOM THERE IS @ THAT JOINT FILLS WITH TRANS FLUID -VIA HOLES??? -TO LUBE THE I/O BEARINGS AND THE DIFF SIDE IS SEALED? WAS HOPING BOT SIDES WERE SEALED , BUT THATS NOT PAR FOR ME AND WOULD MAKE THIS WAY TO EASY,HAHA. YOU THINK CAPPING IT AND EXTENDING IT WOULD BE BETTER OR A QUART EXTRA FLUID IN THE TUNNEL DO THE TRICK? IS THERE PRESSURE INVOLVED ANYWHERE IN THE BACK PORTION WHERE THIS JUNCTION IS AND WILL THAT EXTENSION EFFECT PERFORMANCE? TOTAL DARK AREA FOR ME CAN YOU TELL? ANY DRAWINGS/PICS WOULD BE GREATLY APPRECIATED. I DID PICK UP WEDNESDAY- A '84 FINAL EDITION CADDY REPAIR MANUAL FROM THE CAD DEALER I DO WORK FOR. EVEN THOUGH IT IS VERY INTENSE READING NOT THAT PICTURESQUE AS A WHOLE....LOL, AND THE TRANS AND DIFF ARE SEPARATE SECTIONS SO NO GOOD INFO ABOUT THE JUCTION ITSELF, SAD, CUZ IT MAKES ME FEEL OLD, BUT THE MECHANICS THERE ARE TO YOUNG TO REMEMBER THIS TRANS AND LOOK @ ME LIKE IM TALKING FRENCH. THANKS.... JUST HEARING THE POSSITIVE SOUNDS IN YOUR WORDING IS ENUFF TO GET ME FIRED UP ON ACCOMPLISHING THIS SETUP. RON

This pic sucks, but using the 4 runner diff moved the axle centerline about 7" to the rear and raised the engine a an inch or two.

[This message has been edited by fieroguru (edited 05-03-2008).]

I did a set up useing a bmw final drive unit for a guy buiding a kit car but it was for a th425 and it was a sbc reversed rotation setup. Although he never finished the rest of the project it was a very neat setup. I just tossed the th425 final drive and fabed a frame to support the bmw final drive. I made a backing plate for the th425 with a seal, and used some various drive line parts for a small drive shaft. I think it added a total of 8 inches to the driveline. It might be worth looking at for your project, the bmw final drives are cheap and come in some great ratios. I think the guy got a 3.90 lsd for $200.00 with low mileage.

For that matter, I think a th400 output tailshaft will fit up, as well. Might be worth a trip to the junkyard, just to get the juices flowing.

David Breeze

Let's see if this works better...

SO IM QUESSING I DONT HAVE TO STAY WITH THE OLD FINAL DRIVE THAT OTHER OPTIONS ARE OUT THERE. THATS COOL. BMW, TOYOTA, AND SO ON, WHAT ABOUT AXLES, USE THE AXLES THAT THOSE CARS COME WITH IM QUESSING AND MAKE THEM FIT???? OR ARE THESE PARTS ALL MIXN AN MATCHING. IM OFF TO THE YARD TO DO SOME SCOUTING LOL