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Dave,

You are scaring me. Are you SURE you aren't a rocket scientist?

When I talked to Barry at Shadbolt cams he mentioned that the asymetrical cam profile was due to the cam contacting on the follower which is mounted on the side. On a pushrod engine or an overhead cam engine with direct acting cam-on-valve, the pattern would be symmetrical.

He suggested that the assymetry was to equalize the rise and fall rates which would be different because of the changing rocker ratio. That is so cool that you noticed it. He had to point it out to me.

I also suspect that you are AGAIN right on the money with the variable rocker ratio. When I was measuring the stock cam height I measured a rocker ratio of about 1.73:1. On the TRD cam with increased lift, the rocker ratio at maximum lift was about 1.79:1. I thought that was too big a difference to be a measurement error. I assume that as the taller lobe sweeps to the right, the leverage of the system is increased. Thank you for pointing that out. I was feeling very guilty for poor measurement technique.
 
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