Tail shaft interchange th200, th350

[Steve Bakken]

My son just picked up a 350 rocket/th350 for his 78 Calais to replace his 260/th200. His Cutlass is running the stock 2.29 rear end ratio and I know the new trans speedo drive is calculated for much steeper gears. Does anyone know if the tail shafts will interchange? That way he can keep his speedo correct.

 

[Ribbedroof]

Tailshaft housing is part of the case on a 200

Some TH350 use the same driven gear sleeve as the TH200, so it could be swapped (assuming the drive gear is correct) with no change in net reading

 

[Steve Bakken]

The easy solution would be to just leave the 200 in there, but I don't imagine it was designed to handle the additional torque of the 350