What length is the stock drive shaft and what series of U joint does the stock Type O rear use? I may need to use a junk yard TH400 with a Transgo shift kit and high stall while I build the TH2004R. I already modified the emergency brake cables and know it needs a 32 spline yoke.

 

Surprised no one knows this, even the U joint series is helpful. I am not touching my stock TH350 driveshaft. I have a stock 88 Cutlass and 80's big car driveshaft to cut and add the right yoke and U joint in the back. I have seen 54.5" and 55.5" for length searching on here.

 

Your best best is to assemble everything and then measure. Whoever cuts and balances the driveshaft will tell you exactly where to measure. Some shops want from the seal surface to the center of the rearend flange, other want want the measurement from the output shaft to the u joint.

 

Yeah, I need to find a shop to do it and get an estimate. It is more for no down time and a back up trans. Maybe it might be wiser to just spend the money on the 2004R. Decisions.

 

If you have a TH350 trans in the car now, you already have a driveshaft for the 2004R. If your long term plan is the overdrive trans I wouldn’t bother with having a driveshaft made for the 400.

Another option: get a ballpark measurement of the driveshaft length you need. Head to your nearest auto salvage yard with a measuring tape in hand. Look thru their driveshaft collection, you may find something that will work. You might have to swap transmission yokes, worst case your out the cost of a used driveshaft and a couple u joints.

 

Yeah, unfortunately due to unfortunate circumstances, the current temporary Olds 350 won't make another year. Actually, it will only see in town duty this year. Yeah, I currently have a good working TH2004R in my car. I put a TH400 driveshaft wanted in the ads. I want to just focus on getting the motor done. I know where 4 BOP TH400 short tail transmissions are sitting at a wrecker. A Transgo shift kit and 2500+ stall and go while I focus on the Olds 350.