Hello. I have a 1970 Cutlass supreme with original 350 engine and tranny. I am replacing this with 455 engine and 400 turbo. Can I use my existing driveshaft or is it to long or too short for this swap? Any input would be appreciated. Rick

 

Nope, you have 3 options. You can modify your existing driveshaft, have a new one fabricated or locate one for your application. I chose the fabrication route as mine was a 2 piece with the rubber insert. I inserted the T400 yoke into the trans all the way, pulled it out 3/4 of an inch and measured from the center of the ujoint on the yoke to the flat area at the rear differential (center to center). I called the local driveshaft guys and had a steel one fab'd new for about $220 assembled and balanced with new ujoints.

 

1" rather than 3/4" is considered the best by Mark Williams who builds race shafts. They recommend up to 1.25". 3/4" could be too tight in some circumstances.

 

The T400 yoke is really short! My guy's at the driveshaft shop recommended 3/4", it worked on mine with no issues!!

 

So, is there any difference between a 350 turbo yolk and a 400 turbo yolk? I think I would have my existing driveshaft shortened, This may be the easiest, least expensive way.

 

Some yolks are yellower, some are runny, all have plenty of cholesterol.

As for yokes, the TH350 yoke is smaller than the TH400 yoke.

- Eric

 

x2 - lol!!!!

 

You will also need to change your forward and intermediate e-brake cables. The TH400 requires the crossmember to move rearward and the cables hang off the crossmember. The TH400 cables are different as a result.

 

Sorry, I meant yoke. Anyway, will a yoke from another GM A body car with 400 turbo work? Are they the same as Olds?

 

Thanks Joe, I didnt even consider the e brake cables. CHA-CHING! more parts needed!

 

You may not have to change your ebrake cables if you shorten the hook that attatches to the crossmember and then adjust your cable tighter. I installed a 1 inch hook in place of the stock one and it worked fine!