The "stall" speed is a K factor rating(math).. the "flash"
is what you see at the hit of the pedal(max load/rpm)...
as some said.. its hard to get a true readings.. the drop
back or the high gear or on the trans brake with no chip..
I like the trans brake way.. BUT you have to have the trans
brake.. the drop back method is pretty decent but you dont
see the multiplier in the conv but you still see max rpm