ask him again or maybe you got the kind of pulleys wrong because aem doesnt make a crank pulley
they dont make a crank pulley because the stock pulley has a harmonic dampener on it so it absorbs the vibration, but aftermarket underdrive pulley just have the pulley and no harmonic dampener so theres alot of vibration which can and has led to oil pump failure and bearing failure.
if you have a underdrive crank pulley i would get rid of it and go back to stock