What stall torque converter do I need?

Not just the cam but the rear gearing, the final gearing of the transmission and what tires you plan to run, plus the torque and hp of the engine all factor into it. Then you need to figure out just how you really want to run it. a high stall works for racing but can be a pain on the street because it doesn't stop slipping until it hits that RPM so they tend to run hotter as a result. What you really need to do is simple. Get the car together and running, then make a couple runs and see where the engine really start to pick up and make power. Then start tuning it. Once you get it close run it and see where it start to really make power and choose the stall for that rpm. Don't forget that cam will not work with the stock tune in the ECM so that all needs to be figured in. I would say you will likely end up around a 2500 stall speed but be sure to run a large cooler for street use.