Intermittently running rough, stumbling

[rich weyand]

Some other things.

The distributor clamps can also get bent (or get put on upside down) where they don't clamp anymore. Make sure once it is clamped that you can't move it.

Check vacuum can *and* hose to vacuum can (if you have them). Also, put vacuum advance on manifold vacuum, not ported vacuum.

Check freedom of movement of vacuum advance mech and mechanical advance mech (if you have them).