4l60/700r4 is a good choice. Might be a bit shorter than the TH400, and I know the output shaft is different, so there could be driveshaft length issues.
700R4 is the way to go it is a 4spd unit w/ od. It is a few inches shorter than a TH400 & mounting location is not the same. Drive shaft yoke and length will be different and you will need to fab up either a new cross member or creative mounting. If you get seriuos pm me or email me, site is below. I can give you more help.
Seen your website. Your not too far away from my folks. Just a border away. They are in NW Ontario.
Do you install the transmissions, or just rebuild them specifically to the needs people want?
This corvette they have is used primarily for cruising around. Not dragging or sport driving. But a solid feel is nice. It doesn't need to feel all slippy.
700's have a few variations, externally they are the same.(as far as 2wd/4x4) Ideally you can get yourself a pre87 unit then I can tell ya how to make to lock-up with out electrical hookups. I build & install so anything you are lookin for just ask. The torque converter that you'll find in any stock unit should work ok for you, the stall speed change is minimal. If you'd like to get a reman I can ship you one out too. That way you know you have the right stall.
Why bother with a 700 when you could do a 200-4R ? The 200 has the same gear ratios as the TH-400, but with an overdrive gear. The 700 is heavier and has a horrendous 1-2 gear drop. The 200 can be made very strong and reliable. I have a friend that builds them for GN's running 9 second ET's.
2004R's are harder to find and to find parts for. They can be built up
but it's costly to beef one up since they are inherently weak. They are after all a 200C with an added OD. On the drag track they like them since the guts are small and light.
