The VSVs very rarely fail. Our you sure they are bad ? Also the locations of the vacuum switch valves are diff from year to year and in the early trucks they are completely diff then in 82. What is causing you to think the vsvs are bad. I gather its a smog issue.......is the egr not switching on when it should ? Have you replaced all the vacuum lines ? There can be a ton reasons which can identify as a bad vsv. Heck the list of questions just to get a general idea what is going on would be like 20-30 long.
I wouldnt buy new ones till you narrow it down.
