What Primer To Use?

I haven't done body work for about 23 years. I'm starting on my 74 Dart Sport, that I'm cloning to a 70-71 Duster.
The primer I used in the past was porous, and of course would allow rust to form.
What should I use as I strip the body and do various bond repairs and weld patches?
I plan on stripping the car w/ a sander as I go.
I'm going to spray the color in the jambs (doors off), trunk and engine compartment, too, if that matters any. I'd love to spray the body too. But space is a big problem there.