how to find out the stall of a converter??????????????pic included

i know that converters are very broad range of flash points do to lts of different variables but i was trying to give an estimate. that was the reason i asked the diameter to see what he had... just trying to help...

I'm sorry if that came out contrary. I didn't mean it like that. I simply used 10" as a general reference....since it was already used. I just meant ANY diameter converter. Sorry bout that.