Originally Posted by Builder
GMC used Pontiac engines
What years and what engines?

Pontiac engines were available in GMC trucks from 1955 onwards (New Design GMC trucks)

older GMC engines (1955 Z-series and earlier) GMC trucks:
The GMC 228, 248, 279, 302 (6-cylinder engines, referred-to by Frasnk50, above) were not Pontiac engines.