For everyone who keeps asking me, yes, you can use an ARC125cc Typhoon on an AKA track and yes, you can turn up and enter any offered TAG 125 class with one and you can't be denied or disqualified. If in doubt, just ask Mr. Farley what happened when Paul Laskazewski used an engine that was approved for the class but had been omitted from the manual. It's not a problem. If the NKC have approved it, it's legal. AMSAC said so.
Obviously an addendum should be issued to make sure there's no recurrence of the problem described above and you need not take my word for it, here is the relevant section from the TAG 125 rules put to the NKC and the NKC's unanimous minute approving them.
NKC Meeting Minutes
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