Chevy Torque converter in a 904?

Some converter manufacturers use "balloons" from other car manufacturers. I have seen them use pinto balloons so it could quite possibly be a citation balloon. If you want a 10" convertor you have to use a different core. My only question would be, you can't tell a stall speed of a converter by looking at it. You can have all kinds of stall speeds variations in a given converter diameter. So either he is trying to dazzle you with brilliance or baffle you with bulls**t.