Agree - it is a first generation Olds Rocket. FWIW, Olds got it pretty much right, from moment one. As the first mid-price OHV "High Compression" V-8 there was no margin for error, they were betting the brand on it.

In the cool light of history, the engine was overbuilt for the task, with high quality materials, all-forged rotating assemblies and sturdy architecture that could handle racing levels of power.

Even later Mk. II engines 330-400-425 use many of the original dimensions; the American Petroleum Institute (API) benchmark test engine was the Olds 350 for decades.

When the engine plant closed in the early 90's, much of the tooling in the building had been there since late '48 when it was installed.