How much HP and what do you think it will run.

It's going on a Dyno correct?
If so you'll have your data. You'll need to be looking at your peak torque numbers rpm and weight of car. The horsepower and weight can get you sorta close on a calculator. Then just make up your mind on which rpm you want to cross at and what your shift points need to be.
Chances are better 4.10-4.56.
did i remember correctly that stall is 300 rpm over max torque, dont forget to calculate converter slippage