I think that what they call a classic wah-wah sound. The thing that just blend your tone into something soft and spacy in a warm way.

What pedal should give me this sound?
Oh, that's cream. I think EC used a vox wah with an SG/ES355 into a JTM45 or similar at the time.
I don't give a shit if you listen to me or not
Vox Clyde McCoy wah.
Schecter Gryphon; Ibanez AEG20E
Peavey Rage 158 ; TRAYNOR YCS50
EHX Big Muff Pi; Dunlop CryBaby GCB-95 (modded); MXR M-108 10-band; DigiTech JamMan Looper
EC's setup at the time

1964 Gibson SG ( The Fool)

Fuzz Face ( or some other fuzz pedal)

Vox Wah

Marshall Superlead ( El34s)

Now, Vox's new Clyde Mcoy wah is great, but it isn't as good as the original. For a much closer replica of the original, try the Fulltone Clyde ; you won't be disappointed!