The Pertronix Ignitor uses a "power transistor" to ground the coil instead of the points. A timing circuit "fires" the transistor, matching revolutions to the distributor rotor - and holding the coil ground for a time interval equal to the (old term) "dwell". The "dwell" and the primary resistance of the coil determine how many amps flow through the transistor and for how long. If you use too small of a primary resistance - the coil alone - or coil plus ballast resistor ....it will fry the power transistor in the Pertronix. Too many amps will flow.

You can test a coil by using a VOM meter across the primary terminals - but the value is typically low and the scale would have to be like "0-10" or smaller - or maybe a digital type.

I would suggest you use an "E-core" coil such as is found in the late Ford TFI electronic ignition system. They are made to run at higher temperatures - and have no oil inside to cook. The steel frame for the coil is shaped like an "E" - they are square and attach with four screws to an upright mounting bracket. There are many of them available - including the stock Ford type - and you would simply need to research the OHMs - or measure it directly.

On my outfit I chose to use an MSD "Streetfire" E-core coil - primary resistance is .44 OHMs and I paired it up with an MSD ballast resistor of .88 OHMs for a total of 1.3 OHMs. But...I am using a different controller than you and at the dwell it provides, the current won't cook the transistor immediately. To use an early Ignitor, the ballast resistance would have to be higher to create a sum greater than 1.5 OHMs.  

The heat in the inductive spark comes from the amps in the coil primary - and importantly, how fast it can get fully energized to "fire". As the engine runs at higher and higher speeds, the time available to "saturate" the coil primary with amps gets smaller and smaller. Modern coils have low primary resistance to enhance the speed of saturation - and they are constucted with high temperature insulation - no more oil to cook.

Older inductive ignition systems had to have both considerable primary resistance in the coil and oil for cooling in order to survive with an acceptable lifetime. This was pretty much matched by the thermal capacity of the points so the system had some similar limits. High performance dual point distributors were invented to increase the available coil charge time (dwell) as the rev's went up - and share the heat load on the points. In some instances the stock coil life dropped in that sort of application - remember when everyone went to using the big Mallory coils for the "hot ignition set-up"? Way more thermal capacity.

When we switch to an "electronic" ignition - using a transistor to ground the coil circuit instead of the points - it has a lot more thermal capacity - can carry more amps with an acceptable lifetime. As a result, its OK to run more voltage into the high temperature / lower primary resistance coils (full battery / charging system volts is fine) and the combined coil primary / ballast resistance can drop to 1.5 OHMs (and less in some circumstances). The spark in the chamber is still the 10-12,000 volts as before - but the heat goes way up due to more amps. Coils for use with electronic ignitions tend to be made for "all position" mounting - but primary resistance could be lower than you want it to be for use with points.