If you want original, it will be a treasure hunt, and any seats you find will surely require much work. Store-bought seat rebuild kits for my 1964 & 65 cost ~$700 (vinyl & foam), so I went w/ more modern seats (Cobra conv. pair $50 & Sebring pair $100), since that also allows a shoulder belt which I feel naked without. Both sets have a power driver's seat, which is no thrill given the added weight and wiring. You do have to rig some brackets to mount to the floor.
Pretty sure your year used a 19" wide radiator (until 1964?). After that, they cut the opening to 22" and in the mid-70's to 26" wide. But, you could install a 22" radiator and it would give more cooling. The air will spread out to go thru the whole radiator, though some people cut the opening wider. You surely have a slant (V-8's didn't start until 1964) and in later years the slants came w/ a narrower radiator (19"W?) w/ a metal filler on the side. So, don't fear using a 19"W one, but more cooling is always better.
