Walt;
The (dual point) Mallory must be 'set up' on a "distributor machine" while turning and this may be why there were problems. Normally they only require an adjustment about every 20,000 miles +/-.
The kit to convert is around $70 for a 50s dist.
The (expensive) racing units are for just that, high compression/high RPM use.
I'm not familar with the Petrox unit but many like it etc.
Happy trails.
