It might be necessary to go to a bigger converter core to get the characteristics you want. I raced a 535 in a 3400 lb car with a stock 340 converter, which is 10 3/4 inch core. The stocker only lasted six passes but stalled to 3800 behind that motor with 906 heads. You should be able to get somewhere around 3000, to 3200 (maybe even 3400?)with a stock type configuration but modified guts to make it live. Then the 3.23 gears and tall tires won't make the converter slip too much. The bigger core simply has more leverage which helps reduce slip. I can relate to the rpm problem for long cruises. I even have a lockup trans, and 3.55 gears with 28.3 inch tall tires is still buzzing the motor more than I like. Funny, forty years ago it didn't seem so bad. Guys were running more gear on the street all the time, and driving freeways with them.