Some amount of discussion lately about the lowered amounts of zinc and phosphorous in conventional motor oils. Not so with HDEO, but according to some, these lesser amounts will be the trend even for HDEO. This is more an issue for flat tappet valve trains as it applies to increased wear, particularly more radical cam profiles and valve spring pressures. Now, I`ve been driving a 1965 OHV Volvo whose valvetrain is considerably quieter since using Havoline 10W-40. Havoline has a bunch of moly. I intend to use HDEO as they have increased amounts of zinc and phosphorous. My question is: Does moly do as good a job of protecting flat tappet valve trains as does zinc and phosphorous. Guess the solution would be Schaeffers 15W-40 which has a lot of all three (if cost is not a factor-which it always is!).