I noticed you didn't get a response. I bought the 62mm a month ago and EC said not one has been returned or scattered. My car went apeshit in immediate gains with it and the NW single CAI. I have new tires all the way around and was breaking traction on the shift from 1 to 2, and 2 to 3 at WOT. I have a dyno tune set for Sept. 2. Then I'm done with mods. I drive it every day and I'm not on the track so I'm not putting any more into the motor. I've built alot of small block chevies and big block mopars and this car runs like a 350 stroker I built years ago in torque and HP. Also, I've read about fuel mods being needed with the 62mm pulley. I'm not feeling it but dyno will tell the story. I might be lean at the high end 5000 to 6000rpm range. Again dyno tune will pick it up. Stock belt worked with no evident slippage. I'm happy. I will know more after the dyno tune but the gains from the pulley were very significant and the CAI a noticable increase. I expect the tune to bring it all together. I will post dyno results if you would like them.