What is the best way to track a short in my 1974 mgb

Put an ammeter between the + terminal of the battery and the cable that would normally be attached to the terminal. The meter should show an abnormally high reading. Remove fuses in turn until the reading drops. This will identify the circuit at fault. Now you just need to check each item and the cabling on that one circuit.

yes, that is called a parasitic draw test, but he forgot a few details, yes use a meter that reads volts, amps, ohms, agreed, but OWNER PLEASE CORRECT ME, wasn't that a 6 volt system, that of which power cuts on the ground side?????????? if not, then forget that question, it is early for me, or i was thinking of the 2 6-volt batteries????....but i believe it was. regardless, how is your voltage regulator???message me for correction/accuracy please...

Early MGBs used 2 6v batteries in series (i.e. 12v), later (rubber bumper) cars used a single 12v battery.