Question: The 1967 Trans-American Championship was the second running of the Sports Car Club of America's Trans-Am Series, which year would also mark the debut of Mercury, with Dan Gurney winning at Green Valley for the company in its new Cougar, Gurney also reached racing's highest levels starting in which year?
Sentence (from "1967 Trans-American Sedan Championship"): After the dominance of Alfa Romeo in the under 2000cc class in 1966, Porsche would rise to prominence, starting a dynasty that would last for several years.
Relevant evidence: No