He just had a normal Crybaby wah back then. What’s interesting though is that J often times had his wah after his big muff instead of before it.

As you may or may not know, most put the wah first in their line of pedals, because it gives it the most sweep and response. Put it after pedals, especially fuzz pedals like the Big Muff, can give some real nasty sounds (Watt’s cover of Maggot Brain showcases this pretty well). That’s probably how J got that sound early on. So I suggest getting a wah, putting it after a nice, loud pedal, turning your amp full on, and just cutting loose