Time to rebuild?

Thanks, Bill. That's the kind of different perspective I was looking for. I'll try the hand-turn test this afternoon. I do recall last time I turned the engine by hand it was pretty hard to turn, and someone suggested removing the spark plugs next time to relieve pressure. I think that was when I was changing the fuel pump.

The carb is a Holley 1945 that was installed new right before I bought the car. I haven't looked inside it.