I assume you checked the dwell?
Have you put a vacuum gage on it?
fresh gas?
possibilities are:
improper dwell
vacuum leak
low float level
power valve not working
plugged metering jet
broken valve spring
burnt valve
blown head gasket between cylinders
air pump divert valve malfunction (Califonia Air pump equip.)
checking compression (with all plugs out) would help eliminate some possibilities.
A tailpipe sniffer would help with others.
If the vac gage bounces, that will tell you about the valves also.
