perhaps no other decade has contributed more to the development of the truck than the 1950s. petrol engines and rudimentary pre-chamber-combustion diesel engines were superseded by efficient direct-injection diesel engines.

How would the previous sentence be correctly capitalized?
Perhaps no other decade has contributed more to the development of the truck than the 1950s. Petrol engines and rudimentary pre-chamber-combustion diesel engines were superseded by efficient direct-injection diesel engines.