Shaun. there is a single groove for non-AC trucks and the double groove for trucks with AC. Apparently it was done for the fan as they only go crank, WP and PS. AC is separate, but does cross the outer groove of the WP pulley. Alternator is crank and alternator only and air pumps are run off the alternator pulley.
I definitely do not miss trying to find that "matched set" for the power steering pump.
Bill AKA "LOBO"
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"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 2009 Flex Limited with factory tow package
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413