Your shop manual says the OEM coil has a primary resistance of:
It also says your OEM ballast resistor should measure:
If the Flame Thrower is a 1.5 ohm coil, it is the same as your original coil and it will work well with your original ballast resistor.
For proper ballast resistance on the 3 ohm Flame Thrower, call Pertronix. To me, it looks suspiciously like an 'internal resistance' coil because if I add the OEM ballast resistance and the OEM coil resistance, I come up with about three ohms. - Dave