Most songs aren't as good when the instrumentals are stripped out, but Marvin Gaye's vocals in "I Heard it Through the Grapevine" are so powerful and haunting that they don't need accompaniment.
From Open Culture:
Marvin Gaye's mega-hit, "I Heard it Through the Grapevine," turns 50 this year.
Smokey Robinson and Gladys Knight got the first cracks at the now iconic Barrett Strong-Norman Whitfield tune, but Gaye's 1968 rendition is the famous one, the bestselling Motown single of the decade.
Gaye's former brother-in-law, Motown Records founder Berry Gordy, is perhaps the only one who wasn't impressed, refusing to believe it could be a viable single until its enthusiastic reception by radio DJs and the listening public convinced him otherwise. In short order, In The Groove, the 1968 album on which it first appeared, was retitled with the name of its monster hit.