yes they will interchange . you should have mo major problems switching them.
I believe that is 30 to 40 PSI
the best way to find out is to look at another truck engine with the same engine and the same year. There are a lot of variations to 2.9 as well as others and every year they are changes to vacuum...
On the passenger side where the carpet goes up under the dash. Pull the carpet back and it will be on the left.
not sure exactly what it took to do this but you might check it out http://www.youtube.com/watch?v=DTaQY7RSagE