Ordinary HEI usually works just fine, it is multi-spark control units like MSD that create difficulties with most lights, my old dial-back Sears Craftsman is one of the few old ones that can do them as well.

I took a serious look at many lights a short while back, and if I had to buy a new one, this multi-function Equus Pro Timing Light would definitely be the one. It is also compatible with points, electronic, computer controlled, DIS and multi-spark ignition systems, and it is very practical, in that it show revs and lots of other info right there on the same dial as the retard/advance numbers.

Olaf.

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Aspenized