727 build?

I understand what your saying about your horse power. I'm not trying to be insulting. However being realistic will bring you much more joy when your driving her. We all build 400+ horse and then go drive them on the street and never get out of the 285 300 range at most. It is better to set up a street driven car in the operating range and have pure pleasure. Now had you said street/race. I would have a different answer. There is no way I want a 4600 stall on a street car. Match it to your engine, trans, axle, tires, day to day operating range and the way you drive. It may be a little tamer but you'll enjoy it more, and a stock trans rebuild/refresh will be fine for your application. I'd be totaling guessing on about a 24 to 28 stall and that feels high in your situation.