Can you lift a Roadmaster?

Not a lot, just and inch or three.

I like my truck but sometimes it's a PITA with a tonneau, on some roads Mr. Truck es verboten.

I'd like a bit of a higher ride, better visibility, not as cloud like ride.

Thoughts?

Rear suspension is easy - just put some longer springs on it and I think you'll be fine. The stock shocks actually have quite a bit of droop travel, so if you are only adding a couple inches I would think it would be okay.

I don't know how it would go at the front. You could probably get an inch or so out of it without too many issues, but the front suspension on these tends to get pretty bump-steery at non stock ride heights in my experience, but at least the arms are relatively long and mostly parallel so should still be able to align it. Astro or c1500 shocks *might* fit for a little more travel and stiffness, but not 100% on that. The mounting is certainly similar.

I've never looked for taller than stock springs for mine, but when I was looking for lowering springs, the Moog interchange had a lot to offer that fit in the stock locations. I think a slight lift is probably pretty doable for a few hundred bucks.

Spring spec for the Caprice 9C1 are your friend. They were taller and a bit stiffer than stock to help squad cars hop curbs and not bottom out. Used ones are probably sagged out after 20 years, but get new ones to the OG specs. 

My guess is that yes you can:

That silver wagon is not on the stock frame - it was put on top of a 3/4 ton truck frame. I think it's out on the west coast somewhere (Oregon?). There are some pics out there of it being used as a plow truck. Certainly an option, but also definitely not the easiest way of doing it.

What am I, the Hulk?  No, I can't lift a Roadmaster.  Hell, I could barely lift a FIAT 500.

Going to follow Adventure Piggy's build quite closely.

do a DONK search, they lift the bubble body all the time.

Probably the sketchiest lift you can imagine, but it's doable for sure.

donk lifts are barely good enough to carry the car itself down the road...

notice the sweet 'steering plate'

also notice the lower control arms are moved down but the upper arms are still in place, they do that with just making taller spindles...

Yup. 

I love how absurd the difference is in wheel arch gap is front to back when those are lifted.  Easy to forget how far tucked the rears are into the fenders.