Just wondering if you guys had any opinions on what harmonic balancer I should be using. I have a supercharger and I when i ordered my SFI approved balancer it turned out to be an underdrive and when I looked for an SFI with a stock diameter I couldn't find one so I was wondering if I should just buy a brand new OEM balancer or just get a smaller pulley on the supercharger also and hope that there is know belt slippage. The only reason I got the SFI is that i heard that you were surpose to use it if you run under 12 seconds in the quarter and i'm pretty sure that I will be but I know that they will never check that at any tracks around here. Right know I leaning toward sending the SFI back to summit and getting a new stock one. Please give any technical knowledge that you can, I know that somebody has some good info for me. Thanks