Three films made a big impact on me in 1978, which was my first year of independence: The Eyes of Laura Mars (Fay Dunaway/great soundtrack/all those fashions); Thank God It's Friday (soundtrack was the ultimate summer hit machine that year); and Grease.
Of the three, it's Grease that endures as an adventure in fun, free-for-all cinema. FWIW, Conway evidently injured himself while performing stunts in the Greased Lightning number, which led to his eventual dependency on pills.
His TV roles, much as I'm sure they paid the bills, were less iconic as his role in Grease. RIP, tortured soul.