55 2nd series GMC trucks were the first to have V8 engines. The engines were almost exactly the same as a 55 Pontiac V8. Differences were lower compression pistons, Bendix/Stromberg carbs and decent looking almost red paint instead of the Pontiac green. 55 was 288 cubic inches (Pontiac advertised 287), 56 was 316 cubic inches (Pontiac advertised 317), 57 was 347 (same as Pontiac). 58 was 336.1" (smaller bore of Pontiac's 370" engine) and 59 was 336.9" (smaller bore of Pontiac's 389). If you have a 54 with a V8 it didn't come from the factory that way.
