Transmission swap!

I need to know if I can put a TH400 from a 1976 Pontiac Grand Prix with a 350ci engine into a 1972 Olds Delta88 with a TH350 and a 350ci engine.
Will the bellhousing bolts line up?
Is the tailshaft lenth correct?
Will the linkage line up?
Any advise would be appreciated!
Thanks.

This is a pretty easy swap. The bell housing and torque converter will bolt up just fine.
The shift linkage will work fine. But, I recall some 400 transmissions had an electric kickdown switch, something the 350 trans does not have. If your 400 trans does have this device, you may have to adapt the electric switch from the GP gas pedal to your Olds.

The driveshaft may fit. I think the tailshaft and yoke will interchange; its the overall length thats an issue. Measure both transmissions to be sure. If it is a different length, a good driveline shop should be able to shorten the driveshaft for about $100.

Finally, the transmission mount may be in a different location. You may have to move the Olds trans crossmember rearwards slightly to fit.

Personally, for all this trouble, I would be in favour of swapping in a THM 700-R4, with the Buick-Olds-Pontiac bell housing. They're a bit rare but they are out there.