I'd heard the hydraulic flat tappet cams required more zinc so I always dumped the VR1 into my 440 at every oil change. Then I heard that even VR1 might not have enough zinc. When I rebuilt my engine I installed a flat tappet hydraulic Lunati cam and lifters.

You'll never believe what I did next. I called the cam maker! Whoa, right?

VR1 is adequate.

And if you don't want to run 20w-50 you can get some of the local parts stores to order cases of the other weights. Valvoline makes the VR1 in 10w-30 and 10w-40. My local O'Reilly will order cases but AutoZone won't. You also have to find the right person at these types of stores because, or course, some of the people are new and clueless.