09-13 LS9 ZR1 Upper Pulley

If you are looking to increase the boost in your C6 ZR1 Corvette by approx. 6-10 lbs (depending on modifications already done), install Modified Corvettes's 2.38 upper pulley.

Note:Must use a 82.5" belt with a 76mm idler pulley. Tuning is required. Do not attempt to run the Corvette without a knowledgeable calibrator to recalibrate the PCM. No Discount.