If it were the fuel pump I would say you would have very different symptoms.

The dizzie could have hesitant weights, dirty points, incorrect points gap, dirty nodes in the cap, bad leads, could even be the coil?

Check the spark is good and clean the spark plugs while you are at it, also check the spark plug gaps are okay. Following that check the vacuum advance is connected and working properly.

I'm not sure if you have a spare dizzie but replacing it with another unit as a trial and error is somewhat easier. Or buy an electronic one and put that in place of the stock one?