Engine size is a confirmed 261. The small coolant holes in between several cylinders, the head casting number matches to a 261. It was painted yellow (only 261's appear to have been painted yellow). I still haven't uncovered the actual engine casting number but the engine id is C156, so I think the engine was built in early 1956.
Emmett, George's son, remember's putting that engine in to give the truck more power. I haven't determined whether or not it has the bigger carburetor for the 261 or it was the original carb for the earlier engine.
