Replacing 1977 Pontiac Bonneville's transmission

I have a 1977 Pontiac Bonneville with the Metric 200 transmission. It is failing. I want to replace it with a THM 350. Is this a direct swap with the proper length shaft? What should a rebuilt cost?

A 350 and the 200 are the same size externally. You can buy a 350 trans from performance parts suppliers for $1800 or so. You will need a new torque converter - another $200 or so. I read that the 200 uses a throttle kickdown linkage where the 350 did not. The 350 may need a vacuum line connection to the engine for that function, not sure.

Thanks for the info. Not sure the car is even worth that much. It runs ok when it has enough fluid, but it leaks like crazy.