Engie oil

[V8 Bob]

Originally Posted by TomC750

I just ran across an official Ford chart for my '41 that lists oil viscosity for different temperature ranges. I was surprised that 40 weight was listed for summer, when I had planned on 30 weight. Perhaps I should consider 10-40? Typo in title, Supposed to say "Engine oil!"
What say you folks?

IMO, you should NOT run a heavier weight oil than your engine really needs, and this requires an accurate oil pressure gauge to know for sure. Both my flatheads, one stock I've owned for 24+ years with no known previous history, and one fresh and highly modified use 10W30, resulting in very good low and high RPM oil pressure. Heavier-than-needed oil viscosity is not only harder on the oil pump and related gearing, but takes longer to circulate to critical areas especially in colder climates.
I would forget about what oil was "listed" 80+ years ago and simply use a quality modern "detergent" oil with the appropriate weight for your engine and usage.