What engine is this?

[markreed]

Just bought a "new" truck. '64 GMC 1000 series.

I have been looking over the engine, and I cannot seem to figure out what it is. I am relatively new to older modeled engines. My first thoughts were that is was a 350, ive been told that is the easiest swap to make. Also the intake manifold is a "Performer 350 Olds." Some sort of edlebrock carb.

That being said, the oil fill tube looks more like one that would be on a 327. I also don't know if the valve cover bolts are normally offset on a 350?

Anywho, here is a low quality picture. I can take different views or whatever may help.