1990 camaro iroc Please Answer?

Hello all ,
thanks for reading first off all.

okay so I purchased a 1990 iroc -z28
well before I purchase the car I asked the owner the mileage and he said the body reads 121,000 , but the engine has 75,000. So the day I went to go buy the car I asked him if there was a way he can proove that it had 75,000 miles and he said thats what the the prevoise owner told him.
So now im having doubts about the actual mileage.
is thier any way I can find out ???

not really, if the engine runs good and is tuned up well. who cares what the mileage is?