Differences among the years are relatively minor. Most obvious is the grille design. You'll get lots of opinions which is "better".

Advice depends on what you're going to do with it. Resto / Show? 216 is a cool original. Want to drive it a lot, but keep it original? Look for a full oil pressure 235 (later years). Gonna rod it? Motor is less important.

So, what are your plans?

Cheers,
mark.
'51 3100