New cap, rotor, points and condenser. Plug wires are in great shape. Its weird when using my electronic dwell / tach meter the rpms jump 750, 800, 760, 750, 850 etc. When setting the timing you look at the timing mark indicator and the engine burps and the timing mark jumps. So every time this burp happens the rpms and timing jump. Like m m m m (burp), m m m m (burp). Anyone have any ideas. All hoses replaced with silicone. Good compression. No vacuum leaks I know of. 79' 20,000 miles

 

Ive heard with silicone hoses they sometimes leak, or come off so i would say glue them on or something to make sure you have no leaks

 

You sure you didn't feed your car a big mac from McDonalds? Thats what it sounds like to me.

I'm just messin with ya. One of the silicon hoses could have split, or you do actually have a vacuum leak somewhere. Your idle mixture could also be off. I know when my car was running rich, it did basically the same thing.

 

I know for sure on my 79 if its running rich it will run as you say. Lean it out a little bit and be ready to slightly turn up the idle speed. The mixture is on the bottom, and the speed is the top big head screw. Its not really hard and was pretty weird when I first discovered it.