People were running any damn thing through a Leslie that they could figure out a way to run through one. This sound of his seems to me to be very much rooted in a Leslie.
Vinnie Bell was the same guy who popularized (or did something with, maybe even invented?) the Coral electric sitar, right?
oh, look here: Help me figure out this famous but mysterious effect | The Gear Page
My dad used to be a big Vinnie Bell fan. The sound Vinnie is using is his Coral Sitar through a wah pedal and then some kind of rotary speaker effect combined with tape delay. Since he was making this sound before 1970, the rotary effect would most likely have been a Leslie or a Univibe, since electronic phasers didn't come around until the early 70's. The wah is rocked back on the attack of each note to give it the choked, drippy sound.