Listen to what Gene says.

NEVER use non-detergent oil in any engine.

At summer time start-up temperatures a 10W-30 will be a little thinner than the thickness of the straight grade 20W-20 Chevrolet used to recommend.
At winter start up temperatures a 10W-30 will be about the thickness of the straight grade 10W.

In my opinion straight SAE 30 is too thick for cold start-up at ANY ambient temperature.