Gear LS1/MM6 LS6/M12
1st Gear 2.66:1 2.97:1
2nd Gear 1.78:1 2.07:1
3rd Gear 1.30:1 1.43:1
4th Gear 1.00:1 1.00:1
5th Gear 0.74:1 0.84:1
6th Gear 0.50:1 0.56:1
Reverse 2.90:1 3.28:1

The c6z has the same trans gearing as the mm6 or c5 base but has the balls to pull those longer gears.