I currently have a 6.25" 25% under drive pulley and plan on running a 3.4 to 3.85 pulley on my D1sc when I install later this year. Truck has cam, headers, ORY, and MBRP exhaust. There's roughly 4" difference in circumference between the oem crank pulley and my UD pulley. Since procharger ships with a 114" belt with the oem pulley, should I shoot for a 110" to account for the UD pulley and smaller pulley on the SC?

 

Put a truck lower on it. You're losing ProCharger speed with the under drive

if you can find one an LSA take-off lower is ~8% overdrive. I got mine for $40, cheap way to get a couple K more rpm at the blower