stall speed?

Sounds like someone put the 904 behind it. Stock stall on a 340 should have been around 1500 from what I remember so I would think it should be in the 2500 area. But you may have to just try it and see. I have heard some people say they don't like the TCI convertors but I myself have never used them. I have used Dynamic and Turbo Action and they both work great. And on the eng get someone to check and see how it is balanced. If its external it will need weight on the convertor or flex plat but definetly find out as you dont need no vibration headache. Do you know the guy who you got the eng from ? Maybe you can ask him who built it. Ron