#2 is interesting. It's either a 1948-50 F-Series Parcel Delivery truck, or a 1953 or later Ford Vanette, which replaced the F-Series Parcel Delivery. From what little I can see of it, I don't think it's the Vanette.
#6 is a 1960 or 1961 Chevrolet C-Series. I can't think of the cowl insignia being for any other years in that series.
#21, is a 1965 Chevrolet Chevelle, if it's the car you're showing us.