Coil Confusion

Pishta and Kit have it right; the coil resistance is too low for the ignition system. You need to find a coil that has a 1.5 ohm resistance if you stick with the present system. You would be OK on the drag strip but not on the street. And the orange box just exacerbates that. I would ditch it for a standard box for street use.

You may try the Pertronix Flamethower for a stock replacement with a small amount hotter spark. Get the 1.5 ohm version.

Don't just put a higher ballast resistance on it. The problem with higher resistance ballasts is that the rated resistance is when cold. A 1.5 ohm ballast will be about 5 ohms when hot, and then you will have too high a total resistance and spark will be weak when running a while and at high RPM's.

With the coil being hot, it is likely a combination of a low resistance giving higher current than normal, and some shorted turns in the coil.