67 wheel clearance

do 20in wheels fit in the rear of a 67 coupe? is there enough room or is that pushing it a little? i know the KONA (Ring Bros) is running 19s in the rear so just curious if 20s will fit? would low profile tires help?

parts wise, would i need to do anything to the rear and from end if i was to run modern wheels on a vintage?

thanks in advance!