Black Friday Mantis sport UD Pulley special

[The Radium King]

there's a lot of torque on the bolt, and folks in the know say that the bolt is only good for one application of said torque. regarding belts, here's a good resource:

Engine

[BYprodriver]

If it's a 4" diameter pulley, which most of them are, you won't be able to lock the pulley&crank @ TDC.

My original crank bolt is working just fine. It's a 14mm bolt how much is it going to stretch ?

[j.fro]

When I installed mine I saw a 1-2mpg improvement.

[Pdwight]

How can a smaller pulley increase HP in a internal combustion air pump