Stewart from Everett;
I've owned quite a few BBCs and all of them have used a little oil.
I don't think you could go wrong with an HDMO 15W40.
My opinion, and everybody has one just like....well you know the rest of the story
The light weight VS heavy weight engine oils question:
Buster and a few others may someday be elevated to gru status, not buying into the heavier is better mentality that some of have real bad.
Light weights have their place, and I'm sure the oil companies and auto makers are going to make sure they eventually succeed.
The light weights are slowly gaining acceptance.
Its been done before with 5W30 and before that with the first multi-grades.
History does repeat its self.
But not in your siamesed cylinder BBC with its 1965 design and poor rod oiling.
Buster is correct about oil flow being so very important through out his posts.
No statment is more true than with the BB Chev.
Never, did I say never yet? Work your big block hard until the engine is warmed up.
Starting with #2 rod bearing, #6 exhaust cam lobe and on from there you will wipe out your engine in no time at all.
The light weights idiot-proof that habit people have of jumping into their vehicles and hitting 4,000 rpm when the engine starts then roaring off into the morning I-5 traffic.
Do that with your BB Chev and you will be picking your crank up off of the ground, 0W20, 5W30 or not.
Some of those 10W30 HDMOs are quite bullet-proof and make a good BB oil from November to March.
In places like North Dakota, Minnisota, Wisconson, and most of Canada I wouldn't even drive a BBC powered vehicle during the winter
Unless I had no other choice.
That is where the use of a 5W20, 5W30, 5W40, 0W40, or 0W30 engine oil would be not only a wise decision, but necessary for the survival of any engine including the mighty Ford, Chev, and other big block V-8s.
Buster is correct in his posts when he repeats that light weights are not a problem in engines that are designed for them or otherwise recommended by the manufacture.
All others may use them at there own risk.
A few others made the point being that the heavy weights have proven themselves over 10s of years.
It is up to the light weights to prove themselves now.
Not the other way around.