Hi Mr427,
I took a different approach (so what else is new?)
I use a C6 and a 2.88 axle ratio. With 315/35-17s (diameter 25.7") on the rear. I tach 2450 at 65 mph, and can still spin the tires at any speed.
If you find an OD trans (E4OD, 4R700 or whatever) that can fit - i.e., not excessively long - and can stand up to some serious HP, say north of 500, please let us know!
If I could have got a lower ratio, say 2.75, I'd have done that!
BTW don't forget that the torque converter is a significant part of the equation. I use an EDGE with a low (~2200) stall speed.
Regards,
Tom