Buy the pulley from Jim @ Motorvations Motorsports. It is like the Endyn but better...you are less prone ot lose a belt unless Larry has improved on his last design. I have a M45 LS making the numbers below....it is the most powerful JRSC LS known...(I know..sad). A CRV pulley will give you about the same boost gain but then you will run you accessories a little harder. I am running a Motorvations stepper AND a CRV pulley. I have a LHT intercooler so that helps with the scorching intake temps. Good luck!!!