IMHO, the 260 is not worth spending money on (but, of course, the only choice
if you value originality over all else or want a "cooking" motor in line with
the Tiger's stock capabilities), Hipo 289's are better left to the original K
cars they resided in, leaving the 302 as the most pragmatic choice if you
want to mess around trying to build a truly fast Tiger (without the cutting a
tall deck Windsor requires), with the less exotic variants of the 289 a close
second (although good blocks are becoming harder and harder to come by).
BTW, I doubt you will ever have anyone question the "period correctness" of
your car if you retain the toploader and stock engine dress...regardless as
to which motor you choose.
Just another thought,