“Purple Haze” was 1967, right? I’d go for that over “Sunshine of Your Love,” personally. Heck, almost anything off of Are You Experienced?
I have that record. Vinyl-at-the-time album. It’s “shakin’.”
Todd Rundgren’s Want of a Nail. Difficult, intrinsic, and soul blasting.
Let me horn on in here. 1966. California Dreamin’ by the Mamas and the Pappas. One of the most harmonious songs ever. 96 Tears was harder, and good. But California Dreamin’ is right up there with Good Vibrations.
This is a thread for the hardest songs of each year. Think songs that sound the most like metal, before there was metal.
Oh, “hardest.”
Never mind. 
I’d think Iron Butterfly Theme would be up there for 1967… or their Easy Rider for 1970. Thundrous drums.
Edgar Winter band - Frankenstein 1973 - play very loud
Focus - Hocus Pocus - 1972 - play louder still
Rezillos - Somebody’s gonna get their head kicked in - 1978 I know that Fleetwood Mac did it in 1969 but that version is a bit crap
The Stranglers - Should I stay or should I go - 1981
Judas Priest - Take on all the world - 1979 - for the Americans, we got it somewhat sooner
Who rarity from 1967, fairly heavy: Sodding About