I know the buick 350 is a direct swap from my 231. My questions is, is anyone running a th400? I just picked up a 350-4 with 60k on it and still hooked up was a th400 with nice clean fluid awesome $200 score. Trying to figure out if I should split it and just install the motor or stab it in as one. My concerns are yoke size, overall clearance, I think the trans mount will work but not 100%. I do know that the electra manifolds will not work just by eyeball so what manifolds do I need to be looking for
400 require different output shafts and different length shafts, plus you will need to work around the electric kickdown too
To swap to a 400 trans you will need to re-locate the trans cross-member as well. The Parking brake will need to be modified or switched. You would need a custom driveshaft. What trans do you have in the car now? A Th-350 would be what I would use if it has a metric 200 trans. But maybe it already has a Th-350 trans I am not familiar with which trans came behind those V6 engines in that year. Take a pic of the trans pan if you are not sure which trans you have.
I put a 1968 350 and th400 in my 76 skylark, stab them in 1 shot, move the cross member back to the next set of holes, you'll need a different yoke and shorten the drive shaft, I had no issues with my e-brake. they make a elec. kick down that bolts to your throttle linkage at the carb but I put in a floor shifter and just down shift manually.