Besides aftermarket side windows is it possible to add factory side windows to a E150 cargo van?

 

Not easily.

 

While trolling I have seen some people take on this task and add one on the driver side right behind the door. I would caution that if not done properly (tight fit) you will have major leaking issues.

 

Because the OP doesn't elaborate or make it clear what kind of windows he'd add its tough answering the original question.

After market window installation in a bare cargo van is fairly simple IF you're skilled or experienced working with the necessary tools. I've installed or replace close to 50 and when done correctly leaks aren't really a problem.

 

My parts-car is a '79 E150 "Trailer Special" with all the nice windows. The camper van I'm building is an '87 E150 cargo van, with rear windows, and windows in the sliding cargo door. I have thought I'd like to put the RIGHT rear quarter window from the parts-car into this cargo van just to lessen the chance of my making a lane-change into somebody coming up on my right. Presumably the way to do this is to saber-saw a couple of inches of the stamped framing around the window in the parts-car, butt-weld it into a matching hole I'd saw out of the cargo-van, and get a bodyman to take out the distortion from the welding. This project is some ways off, so I haven't asked about it, but as long as it's under discussion here, I'd like to hear more on this.

Are all the replacement seals still available for these windows?

 

just get bigger mirrors