yes the caged pulley attaches at the crank snout and several bolted points to make it secure. it also takes off harmonic stress off the crank. i am using a steel forged cobra jet crank. its supposed to be a decent pulley. right now im using a 2lb upper and 4 lb lower. theoretically im at 14psi. with the ported blower, exhaust and cams i am lower. where at, i dont know.