Odd Door Jambs- Need Advice

So we recently bought a home built in '58 that needs some work. The interior doors all need replaced but they have an odd jamb setup that I have never seen before. All of the jambs are 3.5" deep with walls that are pretty standard 4 9/16". The doors that are in now all seem to be standard widths.

My question is this, is it best to rip this all out to get standard depth jambs so we can trim out the openings, even if it means sacrificing door width? I would think I would have to get narrower door units to shim them out. I have not cut back the surrounding drywall anywhere to see how the existing jambs are mounted yet.

 

You said you wanted to replace the doors but then all your questions are about the jambs??? Do you want to just replace the doors only or are you wanting to replace the doors AND jambs and trim?

If you just want to replace the doors I'd just replace the doors and keep the existing millwork. I like that clean look without the trim on the face of the wall like almost every other home.

 

Yeah, it depends what your plan is. If you plan on replacing doors with prehung and then retrimming those doors with casing then you would have to buzz off your bullnose bead which may be reinforced with expanded metal lath. You would want to be very sure of your wall thicknesses by checking them with a framing square and straight edge.

Cutting those bullnose off would be no fun and it will create a lot of plaster dust. I assume it's plaster and not drywall.