What rpm stall converter should use?

What rpm does it flash at.
Yours and his converter won't be the same flash point, even if they're the same converter. Differences in the vehicle combination will make the flash points different. PTC is a good company, Percision of New Hampton another. There's also Frank Lupo at Dynamic, Edge and Coan. Any of those can build you a quality converter. You need to remember to tell them though, that you want it tight enough for a street car.