High Output Coil

The term high output coil is not well defined. There are canister coils with higher turns ratio for 40-45 kV output, yet still have primary resistance of 1.5 Ohms. They would work with the stock electronic, but as RRR says little benefit.

There are Ford TFI style e-core coils in fancy extruded aluminum mounts, they pack more power, with improved magnetic circuit, and more optimum lower turns ratio. They have a lower primary resistance, only 0.4 to 0.5 Ohms, with a standard ballast, the coil current will likely exceed the stock ignition capabity, and ECM may fail. If you want to use TFT or low primary resistance coils, best to use HEI conversion, or ignition with active dwell control.