Lunati Hydraulic FT Cam users..........

fishmens67 said
oil viscosity has a lot to do with hydraulic lifter failure.
I never had a failure using Valvoline 20/50. Never.
I can run hydraulic cams at 7000 RPM all day long if I wanted to, all day, everyday. lol

Yep. But I’ve been told the lifters now have much tighter internal clearances so a 50 grade doesn’t work as good.

Never verified that, but maybe PRH has.