[Paulporsche]

If you still have points, check or change your points and wires, as ArtZ said. Oops, I see you have changed the wires. Did you check them for continuity and resistance? I had a new one recently w/ a bad end. Make sure they are firmly seated @ both ends.

Do you still have the 76 dizzy or have you swapped in one from a 79? If you still have the older style, as I do, you just have a vac retard, not an advance.

If you have an advance, maybe there is something wrong w/ the advance unit itself, or there is a vacuum leak. Also check the operation of the diz. You say it is in great shape. Does it rotate freely by hand and then spring back? Do you see any gunk or broken springs? Gunter has a great thread on dizzy overhaul.

Checking ignition first, as you are doing, is a good idea. Make sure the fuel pump, and relay, fuse and wiring are good. Then move on to vac leaks and control pressures (WUR).