Five 700R4's are four too many.... I'm thinking about swapping in a TH400 into the '85 Vette. Are there any words of wisdom from anyone who has gone from a 700R4 to a TH400 in their F-body?

 

I wish I had OD, but at least it's bullet proof.

Miles

 

I'm not overly concerned with OD... If I want to go on a road trip, I'll drive my '02.

 

Hay Mojo, imagine seeing you here. You may know about my tranny conversion in progress from seeing it on the Corvetteforum. I would think your biggest problem would be dealing with the torque arm. You either need to put in a long tail shaft 400 and cut your torque arm shorther and then try to figure out how to attach it to the tailshaft or the th400. Or if you get the short tailshaft I don't think your torque arm will be long enough. I worked on my car all day today. I got the th400 with the Gear Vendors bolted up into the car. I cut the torque arm to what I think is going to be the right length. Then I figured out that I can't get the torque arm up in place. So. I fabricated some plates so that I could cut my torque arm in half and then bolt it together. I think that will work well. That way I can put the torque arm in in two pieces and bolt it together. Now I just have to get it lined up right to get the new holes drilled in the end of the torque arm to bolt it to the back of my Gear Vendors. This is a very big job and I have the Gear Vendors with the correct bracket to bolt a torque arm to. I don't know if it would be any easier without the Gear Vendors. I doubt that it would be tho. But it would be much cheaper. I will post some pictures on my web site when I get the torque arm bolted all in.

 

The easiest way to install a TH400 into a third gen is with the B&M swap kit. It includes a new crossmember and all the proper brackets to install things like the torque arm etc.

I don't know what you're supposed to do for a driveshaft when you do the swap. You'll need a TH400 slip yoke for the tranny since it's larger than any other GM tranny slip yoke.

When I put a TH400 in my car, I also installed a 9". I had a custom driveshaft made to length after the installation. I made my own crossmemer, didn't need a torque arm because of ladder bars. Not worried about kick down wiring with a manual valve body.

 

Corvettes don't use a cross member.

 

Bob,

It's true, the GV unit is far and away the best way to go with an auto... I just can't justify that kind of $$. I'll have to see about fabricating a bracket and perhaps a whole torque arm if I end up with a short shaft TH400. I haven't purchased a tranny yet, but the TH400 seems like the best option for price and durability.

 

I know what you mean. I got my th400 and torque converter from Dynamic Converters. He seems like a very knowledgable guy on the phone. I told him what I'm looking for and he remembered that I would need engine braking. He said the only manual valve body available for a th400 that gives engine braking is a forward pattern. That's what I had him make up for me. Looks like he has a lot of big time racers using his transmissions. Check it out. I'm still several days away from getting my car on the road so I can't say whether the tranny works or not yet, hahahaha.

 

Try this link. http://www.dynamicconverters.com/Transmissions.htm

 

Hay Mojo, I just found this thread. It has a picture of Bowtye8's install of the 4l80e. Check out the bracket he made to attach to the torque arm. Looks pretty cool.
http://forums.corvetteforum.com/zerothread?id=219453