The country/rockabilly instrumental Guitar Hop sounds like it was recorded in the 1950s, but it's from 1967 and was on the "B" side of a Vietnam War-themed country vocal, Hill 881.
Although Northland Records was based in Nashville, the Ramblin' Valley Boys apparently were from Michigan. And that's all I know about them. Northland released a dozen or so singles between 1967 and 1970 before calling it quits.
This single is likely the only release by the Ramblin' Valley Boys, whoever they might have been. Guitar Hop is included on two widely available download compilations. Rockabilly Hoodlums, Vol. Two comes from the Netherlands-based Collector Records and was previously released on CD (1995). A few CD copies still seem to be floating around. Expect to pay in the $20 range.
True Rockabilly, Vol. 1 (Serenity, 2014) is a download only release that contains many of the same tracks as Rockabilly Hoodlums, so the latter should probably be your first choice.
Here's another instrumental that's included on Rockabilly Hoodlums.