Oldsragger

hello, im going to put in a newbuild heavyduty custom superturbo powered 400 transmission but it have 3" tail and my th350 have about 6,5" tail of the transmission there the driveshaft goes in to the shaft.

Just Wonder if is it an opinion of driveshaft out there to use instead of cut and weld it longer the driveshaft i have now. AND can i still use the stock transmission crossmember without modify it cause of the shaft?

My car is a b body 79 delta 88.

Thanks for Ideas.

joe_padavano

The short-tail TH400 is the same length as the 200-4R, which was factory-installed in the B-body cars in the 1980s, so a driveshaft from that application will fit your car, with two caveats. First, the driveshaft length may vary for different rear axles, as the dimension from the pinon flange to the axle centerline varies among the GM axles. You need to be sure that the driveshaft you get came from a car with the same rear axle as yours. Second, the TH400 uses a larger yoke on the front of the driveshaft than your TH350 or the 200-4R. You will need a TH400-specific yoke.

Oldsragger

Aha, ok i tought they have the same yokes, I can see if i can find something used

Maybe i will just made a new from a driveshaft dealer and finish balanced,,but it is expencive..

Are th350 and 400 using the same size of crossbearings? I will check my local amcar store,i think they selling yokes there.

joe_padavano

You won't find the correct length driveshaft that also has the correct yoke unless someone built it custom. The correct length factory driveshaft was used on the 200-4R applications and will have the small yoke. You'll need to get a TH400 yoke separately and swap it out.

Oldsragger

OK thanks