Regearing the tranny will alow proper RPM range for any wheel size. If this is not possible ($$$$) then try staying within the factory overall diameter. Or just drive slower to save your motor.
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1970 T1 W/MassIVe 2913cc RAT/?EFI? w/direct fire (very soon) and 915 trans
1962 SC 1776cc SP 944NA brakes, 993 wheels
VKG