Black Mountain has always courted comparisons to the monsters of ’70s rock, but Black Sabbath and Deep Purple wouldn’t have known what to do with a woman as ballsy as Amber Webber, whose house-shaking howl finally moves from the periphery to the center of the band’s rumbling sonic molasses on Wilderness Heart. Webber shares vocals with lead singer Stephen McBean on every track, and their potent chemistry has remade Black Mountain as a stoner-rock Fleetwood Mac on the band’s slickest, most pop-friendly record yet. Naturally, this cloudy-headed version of Stevie Nicks and Lindsey Buckingham trade cocaine for bong rips, teasing an appealing lightness out of acoustic numbers like the proggy “Radiant Hearts” and haunting “Sadie” amid the usual slabs of roaring riffage like “Let Spirits Ride.”