I am looking at putting the March serpentine system on my 396. The conversion kit I am considering is the mch-23020 (performance) or mch-23050 (higher water flow). Difference being in pulley sizes and probably a couple of bucks. Part of me leans to the extra power, which might be minimal, and the other leans to keeping the car running cooler (not sure what that difference is). I also have checked out the pulleys (mch-7630 w/616 p/s for performance) or (7330 w/623 p/s for higher flow) themselves and the savings is about 200 bucks less as the brackets are not included. Has anyone, I am sure there are, done this conversion and are content with the results.