Initial timing needs to be at least 15 Degrees BTDC. The rest of the curve should come in slow till all in at 2600 rpm. Total of 32.

Distributor needs to be check for proper phasing which has been covered before and beaten to death.
A properly phased/curved distributor is required or just keep chasing your tail.

Antifreeze should be 60% water 40% antifreeze
195 degree Thermostat

Quality spark plug wires like Firecores.

Once the initial timing/recurve/phasing and mixture adjustments etc have been resolved you can adjust the jetting.