Run with a timing light hooked up.----One cylinder at a time.----Might be able to spot if it is one cylinder or all that is missing.-----You did replace the wee rubber boots where plug wires screw into the distributor cap ?
There is a huge mis-understanding on carburetors.----It seems it is the first item that folks pick on to start trouble shooting.----And the carburetor upgrade theory will not go away.-----No wonder that fuel injection is so popular !
A 1979 would be white.----A 1979 has electronic ignition.------These motors were essentially the same year after year.----Great fishing motors and easy to maintain.----Check ignition coils.-----Check thermostat.