Thanks for the input oldschool63! Its been bugging me for months about thoses 2 ports. Do you know which vehicles might have used both or the other port, or why?

Funny that Haynes does not mention this - unless I've missed it.

mrstace84 - there are some other threads regarding PCV and re-routing the intake FROM cyl 8 TO the vacuum plenum (tree) to avoid fouling.. sorry I don't have the info handy but will post later if needed.

Not sure if it applies to your 84 truck though ..mine's a 1989.

-rlp