Try 70 @ 1.6k that sucks toping out is probobly rpm related. Higher rpm higher top speed. Lower rpm lower top speed. Also depends on what tire size u got. Right now my truck with 32 in tires and 3.23 should run 150 or so in 3rd theoretically it runs outa steam at 122 mph but with 4.10 its supost to run 118. Oh thats without changin rev limiter at 5500