Only 331 I have is still sitting on the floor after @winduptoy sold it to me for my 40 Merc project. But, I couldn’t ask for a better engine than a Caddy for that project.
I have a pair : One out of a '54 New Yorker in my dirt car and one out of a '56 truck under the stairs as a "spare".
Does anyone know why they cast those lugs on the ends of the truck heads? Has anyone seen anything hung on them?
From looking at their configuration, I have to think they are there to provide mounting options for any variety of add-on accessories. In a pinch, I'm sure they could be used to mount the engine as well.