I agree with you about potential belt slippage with the smaller pulley on the blower. Typically when people add this smaller pulley they add an additional idler pulley and bracket on the left side of the belt or they upsize the 90mm idler pullies to 100mm diameter to wrap the belt for about 88% contact with the upper pulley. Is this what you have seen as well?

However, the belt will definitely travel faster with an increased lower pulley change due to the belt having to travel a further distance around the larger circumference of the increased lower pulley diameter. I would hope the Gatorback belt would stand up to a little extra speed.

Perhaps the ideal situation would be a 2.93 (Lightning)blower pulley and either a 4# or 6# lower crank pully setup. This would likely give you about 7 to 8#'s extra boost from stock. Keep in mind the lower end on these beasts are still only forged pistons and casted rods. Not like the Manley/ARP equipped Cobras.

Remember I am talking about replacing the stock HD 3.25 blower pulley to bring it in line with the Lightning and the pump it up with the lower pulley.

Any one got a thought on this thread?