One other thing about the th425 vs the th325, the final drive assemblies are different also. The th425 has a ring gear that is the same size as a GM 12 bolt rear end while the th325 is smaller, even smaller than a GM 10 bolt I believe. The diff cases are different and are not interchangable from 425 to 325 and the 425 has much bigger diameter axles.

When I read the posts about the TH325, and went back and looked at the pics, I realized something. It is a regular auto with a unit that sends power forward to a diff - in similar fashion to a 4wd truck. The only drawback is additional weight behind the rear axle.

In my case (street-legal racecar) I may be able to remove enough weight from the back of the car to compensate. I am seriously considering fabricating my own gear-drive unit that would send power, via a short torque tube, to a conventional rear-drive pig beside the motor. An intermediate shaft would probably have to pass through the oil pan.

This would allow me to have a wide selection of trannies that can take the abuse I plan to dish out. Hmmmm...

perk

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toddshotrods.com - new biz name & site

If you're going that far, you might as well extend it a little bit and have the engine entirely forward of the axle, in Lamborghini fashion...

quote Originally posted by Will: If you're going that far, you might as well extend it a little bit and have the engine entirely forward of the axle, in Lamborghini fashion...

Thought about it but for some reason I really like the idea of building my car with the stock wheelbase. I guess I like a challenge. I have not ruled a stretch out though.

I have a TH350 that I am going to start experimenting with. Have to pull the cradle out of the car one day so I can mock it up. This setup could make it possible for me to have my development mule Fiero out this summer. I had planned to spend most of this year doing research - mainly for a transmission.

Aren't the TH350 and 700R the same length. The unit I am thinking about would replace the tail section. Would I be able to take it off the TH350 and bolt it on a 700R???

I need to start collecting data on different transmissions now. I want to design the setup so that it can be adapted to mate to a wide varietly of transmissions relatively easily; e.g. changing torque tube lengths or brackets. The constants should be the transfer unit, differential case, motor and differential mounts.

perk - todd’s hot rods

BUMP

bump...trying to keep this thread alive.

[This message has been edited by TONY_C (edited 04-28-2003).]