Thanks everybody for all the great info on this forum! I recently bought a 1964 C10 and was told by the seller the engine is a 350 but want to verify it if possible. I can't get to the casting so am limited to the suffix on the pad in front of the passenger side head. Everything I've found indicates that all suffixes begin with a letter representing the plant location. My suffix begins with a number! The first line is "1M1013" and the second line is "1VP". The valve covers are center bolt which my research says that would make it a 1987 or later. Any help is greatly appreciated. I have a couple very clear photos of the suffix if that will help.
Rick
Rick