Complex sentence: In 1987 the Series 60 ®--the four-cycle heavy-duty engine that would become the signature of the company--was introduced as the first production engine to have integrated electronic controls as a standard feature.
Split into simpler sentences: In 1987 the Series 60--the four-cycle heavy-duty engine for which the company is well known--was introduced. It was the first production engine to have integrated electronic controls as a standard feature.