Randy,
I would suggest getting a 9.5" 2500 stall non lockup Street Terminator Plus with the valve body set to Level 2 calibrations, and it will work good with anything from moderatly to heavily modded. I like the standard ratio gears because the step up to third isn't as big as with the wide ratio gears. But the wide ratio gears will give you harder launches.
Talk directly to Len and tell him how fast you need it. If he can't do it' he will tell you. Make sure to ask for the standard Supercoupe shift point govenor.
David