What Is A Formula 'S' Package 'Year to Year'

The In-Dash Tachometer {lower left hand side} was to be 'Exclusive' with 1965 'Formula S' package.

But, if you knew Plymouth.......... ????

There were some boys on the Production Line during the early-1965 Model Year Production Run who
swore that several of the 1965 273 4-Barrel Engines were equipped with a 'special' camshaft from the
Chrysler Marine Division, as they wanted the early 273 4-Barrel High Performance cars to run like
Tasmanian Devil's.