[Jay S]

If you know what the cam profile looks like (can measure this when a cam is installed) a good general rule for the street is to not set the V series plunger clearance so they operate looser (once the engine is hot) than where the tappet lift of the cam has 1* per .001” of tappet lift on the closing side of the cam. To find that, multiply that tappet lift by the rocker ratio for the max hot clearance. Generally that is the most clearance (hot) that a V series lifter is able to operate well on for the street. It is the quietest operation for the profiles performance gains with V series lifters. Going beyond that is also excessively hard the valve terrain.

I don’t use the Rhoad’s instruction blanket numbers for clearance, because the profile does make a large difference in how the lifters perform.

For a Compcams XE profile, it hit that acceleration at .006” tappet lift. All these cams have the close to the same acceleration at the clearances.

.006” X 1.65 = .0099”

On the exhaust with the magnum profile the same tappet acceleration is at about .007”

.007” X 1.65 = .0115”

For a Melling SPC-8, It hits that tappet acceleration at .009”
.009” X 1.65 = .0148”

For a Crower 60919, it has gentler ramps yet, it hit that same acceleration at .011”. Nearly twice as gentle ramp as an XE.

.011” X 1.65 = .0185”

For racing purposes it is fine to set the clearance higher than those numbers. But for the street, the valve seats and guides get beat up excessively if running more clearance than those clearence numbers.