From the rule book (which you can see on the USAC website):
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Testing
As per the sanction agreement with the USAC Race Organizer, practice and/or testing during the three calendar days prior to
a racing event is not permitted. The term “racing event” means all official USAC sanctioned functions at the track in
conjunction with this race, beginning with the first day of USAC sanctioned practice. Teams who engage in such unauthorized
practice or test runs will be subject to disciplinary action by USAC.
Exceptions: USAC scheduled and sanctioned practices.
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The Turkey Night entry form lists sanctioned practice on Wednesday, then racing events on Thursday. It appears a Sunday through Tuesday practice session would fall into this window.