Past couple of years I've been pouring straight SAE30 into my "77 ford
302 gasoline engine. It's was coming from a barrel which I laid my
hands on several years ago. The label on the barrel actually says:
"Shell High performance diesel engine oil X30"

I've never actually experienced any problems with this oil. As a
matter of fact, I've never experienced any problems with this engine
whatsoever.
But now the bottom of the barrel is showing and so I have to go
shopping for oil again.
Any suggestions for a suitable oil type or brand ? Or should I go for
the same old stuff again.

Since I only use the boat during the summer I never really saw the
point in using a multigrade oil.