Lunati Cam Noise

BTW, my son has a 340 a Crane Z-268-2 cam, and it it quiet as can be with Mobil1 15W50, and Brad Penn 10W30, in it. We have had PRW 1.6 AL needle rockers and now Hughes 1.6 rockers in it with no difference in noise. Lift is in the .485/.505 range IIRC. His 340 has about the same hot idle pressure as you report.

That cam is a slower ramp. But, I am not sure why the ramp rate would make a difference as long as the lifters are not being collapsed during the uplift (seems improbable).

His 340 uses the LA style rocker shaft system. So you may be right on the guide plates; I have to wonder if the pushrods are just flexing and whacking the guide plates. Any signs of contact on the pushrods? Or maybe the rockers studs are flexing and allowing contact. Or the valves are hitting the seats faster....