i have a 84 Z28 with stock drive shaft. and i am trying to bolt it to a 400 turbo tranny, but they dont fit together, the opening in the drive shaft is too small. do you know what size i would need to bolt to a 400? also the cross member and tranny mount dont connect on the new tranny properly any suggestions?

 

Your going to have to get a custom made drive shaft. Take a measurement from the end of the trans tail shaft to the yoke of the rear end. Then go to a local driveshaft shop, and they could make you one.-

 

measure from center to center,not from tranny to rearend.measure from center of transmission yoke to center of rearend yoke were the u-joints set.the crossmember has to be set back about 4inches.i have a 78 and that is about the distance i will have to move mine back.they make a crossmember for a 400.

 

There were a couple of different output shafts on the TH400 the two common ones are a fixed yoke, identified by a bolt hole down the center of the output shaft and a shorter tail housing. the other is a slip yoke design, longer tail housing and no bolt hole in the output shaft. Which one do you have? 400's Ihtink use a 32 spline output and your car should be a 26 spline.

If you have the fixed yoke set up, I have seen people stick a standard slip yoke in and run that, but, I would'nt recomend it, that is not a very stable set up and is prone to vibration and eventual failure as was the case on an 84 BB chevy I fixed at work with the same set up. The tail shaft is to short to support the drive shaft in that configuration. The only way to fix it right is to have a fixed yoke slipshaft built, fixed at both ends and a slip-and-stub-shaft on the trans side. However, if you're making any power eventually you'll beat out the splines on the stubshaft.

If you have the slip yoke set up it's a simple matter of getting the right slip yoke and making it work with the drive shaft. You'll have to check with your local driveline shop to see how they want you to measure for the shaft length. At my shop we prefer you install the slip yoke in the trans leaving about 1" to 1 1/4" gap between the ujoint flange and the tail housing then measure from the center of the ujoint caps at both ends. This measurement needs to be taken with the suspention loaded, car on the ground, just set it up on jackstands.

As for the crossmember, all we've ever done was fabricate till it fit. I'm not sure but there may be some aftermarket companies which may offer solutions to this problem. Sorry I can't help more on that one.

 

your right v-8chevy,he's telling you right.the crossmember can be bought aftermarket or just move your's back and drill new holes in the frame

 

THANKS FOR YOUR HELP GUYS MUCH APPRECIATED