I am installing a Chevy 12 bolt and TH400 in my 70 Cutlass. I will get the conversion U-joint.

Does anybody know how much the driveshaft will need to be shortened or length of new driveshaft. Currently TH350 and O Type Rear in car.

I would like to have it ready when the swap was made instead of measuring and having it made and thus waiting for the new driveline.

 

You need a shaft to fit a Chevelle with a TH400 and 12 bolt. The shop may or may not have those specs.

 

It actually costs pretty close to the same to get a new one as it does to mod your current one.

 

I have an extra one, I can measure it tomorrow

 

That would be really helpful. Thank you.

 

TH400-12 Bolt Chevy Rear

55-1/4" center of front u-joint to center of rear u-joint