Get a pair of dial calipers. Ok, here we go.
1) Measure the width of the lobe at the base circle. This is the "sides" of the lobes around the cam core. Take the measurements from both sides of the base circle, where the lifter rides. Write that number down.
2) Now measure the total lift of the lobe, from the base circle to the peak of the lobe. Write that number down.
3) Now divide the number you got in step 1 by 2. Write that number down.
4) Now subtract the number you got in step 3 from the number you got in step 2. That is your total lobe lift.
5) Since the purple cams were designed for a 1.5 rocker ratio, multiply the number you got in step 4 by 1.5. This will be your total lift at the valve. When you get that final number, report back here and we can very likely tell you which cam you have.
