Engine vibration

I have an engine vibration between 1600-2000 RPM. Below 1600, and, above 2000, the engine runs smooth. I don't believe it's a drive line problem as the engine vibrates when the car is stationary. It also vibrates between 1600-2000 with the clutch engaged or disengaged. Removed drive belts to eliminate fan, alternator, and P/S pump. Still vibrates. All spark plugs firing. All plugs tannish brown. Compression is good. Highest is 175, and, lowest is 165. All others around 170. Vacuum is good. No leaks. Vacuum advance working properly. Harmonic balancer bolt is tight and to spec. Balancer was new about a year ago. Vibration still persisted. No noises (clatter or metallic sounds) coming from engine. Oil pressure good. 25 at idle, 55-60 otherwise. Engine is a 65 389 code WS with manual transmission. Any help/advice appreciated. Thank you.

Maybe your flywheel is out of balance, maybe it wouldn't hurt to try another balancer??

The flywheel is about the only thing that hasn't been checked. I never thought of that. Post's, on other boards I've checked, seem to think it's the flywheel also. Looks like it comes out and off to the machine shop. Will post back with results.

Vibration problem turned out to be the flywheel. Machine shop said it was "way out". Flywheel was rebalanced with pressure plate installed. Engine now smooth as silk from idle to redline.

Good to hear that fixed your problem!!