Torque converters are complex fluidic couplers that join your crank to your transmission. The comment that "Stall is basically how high the engine can rev in gear without the wheels turning" is not quite accurate. Will your car move forward in gear when you let off the brake?! In fact your torque converter actually magnifies the torque off the engine below it's stall speed due to forces within generated by fluid inertia.

The "stall" most people refer to is the flash stall speed of your converter. If you can lock your transmission in 3rd gear for example, this would be the rpm you get to, say, when you stomp on it going 5 mph. The correct stall converter for your car depends on several factors, most importantly the engine characteristics, cam, car weight, and gearing in the rear end.

If you want to find out what you should have call TCI tech or another perfromance trans supplier and ask them what you need based upon your specifics. in general you want a stall speed that puts you somewhere within your cam power band, depending a lot also on your gearing and car weight.

Regards, Kitz