" I fear that with the already huge loss in the non-locking torque converter adding an aftermarket overdrive like a GearVendors unit would mostly result in more loss in the tc.
As the Ford 400 has a big block bellhousing, the matching overdrive Ford transmission is the E4OD, which actually fits with almost no modifications to the car (rear gearbox mount has to be moved and driveshaft shortened, that's all) and comes with a locking torque converter. Sadly, it needs an electronic gearbox control unit - but the MegaSquirt II can provide this with a daughter board, so should I ever find a way to get a low-mileage E4OD shipped on the cheap I shall move on to the MSII. "

If you are interested, I have been building a stand-alone transmission controller for some GM transmissions, I could easily put together one for the E4OD. I could set you up with a complete package from transmission to controller and everything in between. Just a thought.

Buddrow