Tire size for 74 Valiant Brougham

Typically following the three digits identifying the tire's Section Width in millimeters is a two-digit number that identifies the tire's profile or aspect ratio. P225/50R16 91S. The 50 indicates that this tire size's sidewall height (from rim to tread) is 50% of its section width.

I have P215/70/14ww's on my '65 Barracuda...with 5" wide rims (snagged) off of a '66 Belvedere.