Dumb tranny question...

The high stall converter is not the problem. Torque converter drainback is a common problem on torqueflites with stock converters too. But having to wait 10 minutes for it to move isn't. Have you checked the filter lately? Maybe it's plugged up. While your in there check the band adjustment. The leak you mentioned can't be caused by the dust cover missing. The dust cover dosen't seal anything. But if the leak is from the front pump seals the problem could be worse.

The torque converter drainback problem can be remedied (or at least helped alot) by installing one of Trans-go's modified manual valve kits. After you install this kit you can then check your fluid in park like Gm's and Fords. What's happening is the manual valve exhausts while in park so the converter is free to drain back. The problem is much worse when the car is parked up hill also.