I changed the Jackshaft on the supercharger side and the supercharger pulley. Those come stock at 3.2 and 3.2. By going to a 3.4 and 3.0 it is the exact same tension on the belt as stock. It also spins it the same ratio as going from the stillen 8psi pulley (3.2") to the stillen 9psi pulley (2.8")
Here play with this. Our crank diameter is 5.75 and redline is 7500.
https://vortechsuperchargers.com/pag...eed-calculator