been doing some reading on my datsun 260z, found some info about the auto they use, turns out its the same auto as the MQ, the
Jatco 3N71B. this was nissans main auto around the time, a lot of cars (including other manufactures like mazda) use this transmission.
what does this mean, well for starters it may be possible to upgrade it to the locking torque convertor type (if it isnt already) for better cruising. similarily, performance convertors are probably available. also, there are many modifications out there to beef up this transmission, i read they can have manual valve bodies and handle 800+hp and have trans brakes (if you wanted to do some sand dune drag racing). on
viczcar forum, a bloke is offering cheap exchange shift kits for them too.
it also opens the door for a lot of easy conversions. get an engine with its matching 3n71b auto, then it should drop in rather easy, would only need to fab up some engine mounts. so you could get an rx7 rotary in real easy if you wanted. i havent looked into it, but there may be adapters for other engines to the jatco, because it sounds like japans version of the th400. maybe a 2jz conversion or something?