Name The Year: Hardhat diving suit patented by Leonard Norcross, Dixfield, Maine?

Questions

what does nhra stand for??

who recorded the 1951 hit song "down yonder"??

whose song does weird al yankovic spoof with like a surgeon??

who had a us top 40 hit single called "stairway to heaven" in 1960?

goodbye columbus, letting go, portnoy's complaint, the breast.?