There are plenty of places to mount a resistor other than the firewall. Just put it somewhere it will be in the airflow from the fan to keep it cool. I've seen resistors attached to the same bracket that holds the coil onto the side of the engine.
Jerry
That’s the way mine was, but was warned it was not a good idea having another heat source mounted in the coil.
Here is a
[LINK] to where this was discussed in a previous post of mine. Read down a few post to see the discussion.
