Charles,
Honda uses that same style coil in ALL KINDS of stuff! I have a 1990 XR250 which uses an identical coil (different plug cap, though) and have seen them on all sorts of other things from scooters, NSR50s, 80s, etc.

If you have the head conversion on, using the upper coil is a plus anyway. You can use the lower plug cap on an upper coil and the lead is long enough you can mount the coil in the stock location.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
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