Your supercharger has probably been painted more than once over the years… Although black is ‘factory’, I agree they ‘POP’ much better painted the typical Chevy orange (mine is orange)….
 
	I think I’d seal all openings into the blower with duct tape, and then simply coat it with paint remover and let the chemical do the stripping… much easier than trying to sand all the paint off…….
 
	When the supercharger is back to bare aluminum, I’d wash it thoroughly with water, let it dry, then scuff it with 320 sandpaper.. Then, as you say, use the self etching primer, then finish off with the Chevy orange aerosol paint.
 
	(I use Ford type ‘F’ fluid … it is less slippery than some other types, which is better for the ball drive.)
 
	The supercharger belts are self adjusting due to the tensioner spring.