I agree with squeeze,change the oil and see where it lies on the dip stick.I think you need to figure out what year of 350 you have and go from there.
Before you get attacked,there is no such truck as a 1946 AD. 1947.2-1955.1 are the AD models"Advance Design",you have an Art Deco model.

Tim

1951 3100 Chevrolet
1951 Chevrolet Suburban Carryall
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