I dont know if/what your runnin' for hub caps but the temporary spares from GM Mid-sized cars (Cutl***,Monte Carlo,Malibu....) are 16". A buddy of has used them with 7.50X16 on the back of a 32' P/U. It had moon disc on it so you couldnt tell what they were.
Chevy ran different bolt patterns. cars 48 back had 6 lug 16" newer had 5 lug on 4 3/4 bolt pattern some bigger cars like Impala and truck had 5 lug on 5" pattern, with some trucks being 16"