The first Montrose incarnation featured Sammy Hagar on vocals. A lot of hard rockers site their work together as an influence (ironically, even Van Halen!)
"Bad Motor Scooter"
"Rock the Nation" is a pretty cool tune
The first I heard of Montrose's music was in the 80's. He had the band Gamma who still could rock hard, but also moved in a more AOR/melodic rock direction.
Having Mitchell Froom on keyboards added a different dimension to their music.
"Right the First Time"