Yeah, that's way too combo dependant. What you really need, is what ever will flash stall just below the engine's peak torque rpm, and still locks up tight after that stall speed is reached. Being very general, the smaller the OD, the tighter it will act after stall speed is reached, but the harder it is to get a high stall speed from. So an 8" race convertor that stalls at 5500 will be tight above that in high gear, but a 10" that stalls at 3500 may be really loose above that in high gear. To make a perfect convertor requires a small performance window be targeted. That's why it's so hard to get a consensus on "which one is best for me..." type posts. Gearing, tire size and type, car type(weight), engine stroke, horsepower and torque levels, compression, camshaft, intake ports, header collector length all contribute to the final resulting stall speed of a particular convertor in your particular car. Change some of those, and what might have been perfect might now not be..