Old cars are fun, I enjoy it and didn't realize how much I missed driving it!
The poly engine, "polyspherical" was a poor man's hemi, it has similar intake to exhaust design as the hemi, but wasn't as potent and was costly to build. Most people junked it, but there's still a bit of a following of people who are building them. Unlike most typical engines, the poly head was similar to the hemi because the valves were on opposite sides of the head, instead of all in a row like a tyical engine.
The Poly valve train and then a tyical valve train. You can see how the cylinder head design differs on these two:
The intake to exhaust is basically straight through.. here's the poly intake, then a typical intake:
Unless you're a Mopar person, you may not know anything about them. Even a lot of Mopar people couldn't ID my engine when they saw it; but then again, most people just keep theirs completely stock, so mine was a first for a lot of people who never see a poly engine built up like mine is.