Absolute best? That all depends of your presonal preference, riding habits and the relative values you put in factors such as rolling resistance, grip, durability and puncture resistance. However, Continental, Panracer, Schwalbe and Vittoria all make good, 27" tires that handle at least 90psi. Just be sure you buy a tire with a rigid wire bead and not a folding bead. These are not compatible with traditional, 27" rims.

I don't recall whitewall 27" tires during the mid 1970s, but there were definitely skin and amberwalls. Most of the current offerings will be blackwall.