I accidentally posted that with out finishing post. I clarified earlier in thread. Engine oil for 340 with purple cam( unknown specs as I didn’t build engine) I don’t race it just drive it on the street here in Massachusetts from spring to early fall
Ahhh... Royal Purple 10w40 is my choice for you in Massachusetts. I switched to 10w30 RP in my ramcharger and it quieted it down and runs smoother since I started using it.
