Couldn't say, but Lee English does inform me that Bowser still has the original worm gears in stock if you want to experiment...
551-23009 $6.90 each.
Mitch
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Mitch,
Contacted Bowser Last year. The older worm is a double cut also.
They were nice enough to send me the actual shop drawings of the
worm so I could research it.
Thank you for the research.
Andy