you guys need to know ISIS.
Probably the actually closest thing to Jam/metal. Their sound is super heavy combined with some of the deep space Fall '97 psychedelia. At least thats what it makes me feel like... the same feeling. Deeeeep, deeeeep shit.
Fucking ugh, the first few minutes of the opening track are SO brilliant. And then you have the pinnacle song, "Weight", which isn't metal at all, its more like Mogwai, a climbing, escalating ascension of beauty and power with awesome chick vox.
Seriously, if you guys get into anything heavy, Isis will do it for you. I promise. They're SO unique. Its beautiful heavy music. Kind of like Neurosis, I suppose...