[Ryland]

That gear ratio sounds a bit to high for doing direct drive, how about swapping in a manual gear box? automatics waste a lot of energy so most people don't use them, I've only met a few people who have tried and they all said that keeping the automatic was their one big mistake.
Sad to say but I don't think altrax makes a controller large enough for your car, their largest I think is a 72v 400 or 450 amp controller and higher voltage would be better and a 30 second or even a one minute rating of 500 amps or more would be the least that I would do.
I've seen 600 amps while climbing a hill and while starting from a dead stop on the flat.
As for sourcing a fork lift motor, I would start with scrap yards as they tend to sell metal, including motors, by the pound.
Also check out Ben Nelson's DVD on building your own electric car, cheap.