On my SPF #2107 it has standard v belt pulleys with them being std Roush issue on the 427R engine and a regular powermaster alternator and Sanden compressor. Problem I am having is even though the belts are tight the 31.5 length Gates XL 7315 belt looses chunks of belt within maybe a thousand miles if that. I don't apply the AC at warp 9 to intentionally have the Sanden grab the belt and tear the cogs off the inside but I have had 3 belts on the AC pulley within maybe 6000 miles of moderate driving. The backside of the belt has no issues where it rides on the plastic tensioner and alignment does not appear to be an issue. I can only assume that there is a better quality v belt that I can replace it with. I was looking at Gates fleetrunner 9313HD but it appears to be both too wide and a little long at 31 7/8"