322 Buick nailhead I'll bet. They were offered in the big trucks from '57-'59.
Being a Buick fan, I'd go with a nailhead. It doesn't have to be a 322. The newer nailheads are easier to find and parts are more available.

Last edited by 52Carl; 04/09/2020 10:00 PM.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission