Penn Grade One 30 wt break in oil for the break in, then Penn Grade One 10W30. Its essentially the old Kendal GT 1 green oil with an updated additive package, including zzdp and other lubricant enhancers. Described as a semi synthetic. The base dino stock is still refined in Bradford Pennsylvania at the original Kendal refinery using PA crude. I have run that stuff in at least a dozen, if not more, rebuilt early inline chevy 6, including a 261 that I am pretty hard on. Not one single hiccup. Performance flat tappet cam (.492 lift) and all.
DA Lubricants (the old Speed Sport oil) purchased them
https://penngrade1.com/products/hig...nthetic-high-performance-oil-sae-10w-30/
