Brake rpm can be affected by a ton of things, engine combo is the obvious one. But what if he has better brakes then you? He will be able to stall the converter higher, same situation with his vehicle weight vs yours. If I put my 4700 converter that will foot brake 3200 in my duster into say a 3/4 ton truck with my motor I bet it would act totally different.
Hope that helps clear things up
