My "BumbleBeast" it has being running with Valvoline's "MaxLife" semi sinthetyc multigrade oils; however it ran on mineral multigrade oils in the past and after all these years and miles, I decided to change the Hydraulic Lifters with a fresh set of new ones with their tiny holes already Drilled in order to improve the oil flow to them.
The back from a 5/64" drill bit, fits perfect on the tiny holes, but its cutting knives on its other side are wider up to the next size of it, you'll never know how many of these bits I wasted until I found a suitable one that could drill their metal, it is amazingly hard and even tungsten carbide drill bits were wasted by the dozen... so, it is better idea to get the Hydraulic Lifters to a professional lathe shop and let them do that aggrandizement for you, if you can... in my case I done that manually.
Then, a deep cleansing of each Hydraulic Lifter were nessesary.
Eating your Favourite Snack and Soda will help you to be Patient enough...