The impeller in the SC is curved a little less than the S-trim impeller. The SC will make the same boost with less heat but has to be spun harder which can cause extra slippage. I watched my car on the dyno yesterday and I could see the belt slipping, but with a Gatorback belt and making it a little tighter, it would be no problem. Slipping the SC consistently made 10psi at 6500rpms with a 7" crank and the stock 6 rib 3.33" pulley.
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