Engine Questions for a Rookie

[Litespeed54]

Gents,

I have a few questions for you from this rookie. I think I've solved the over heating problem that I was having last week. I replaced the radiator cap, thermostat, and reattached the lower radiator hose. Filled back up with fresh antifreeze and the coolant gauge stays just above cold. So that's good.

But I drove it tonight and once again, after awhile, it becomes sluggish. Almost like the brakes are being applied. I pulled in the garage and the motor seems awfully hot but the gauge doesn't show it. I know the gauge works because I saw it get high last week before my current repairs. Onto my questions.

I'm going to forward you several pictures, focusing on the valve covers. The driver side valve cover has one hole while the passenger side has two holes. The driver side has a hose going into it from the lower part of the carb. The passenger valve cover's front hole is open with nothing going into it. The rear hole has a hose coming out of it and going into the carb, above the flaps.

I've read some things about a PVC valve which I am not sure I have. I also don't know what should be in that don't hole on the passenger side valve cover. Any thoughts? Could that open hole be causing the sluggish problem?

Thanks!