bigger engine in my 91 LTD?

I have the standard 302 (5.0 L) engine with almost 200K. It needs some work, heads and possibly rings, so I'm considering a used engine as apposed to a rebuild. What is the largest engine that will fit in that vehicle?

5.8L was optional on your car.
You could simply build an HO 5.0 and gain some power with that alone.

Thanks for the info...... "simply build an HO 5.0"? please define "simply"..... would that be like the old school "bored and stroked" with a "cam" etc.....

I'm ok with removing the heads and having them reworked but not so sure about rings, a cam, rod bearings, main bearings and "lower end" stuff.

Would the HO give me more power than the 5.8? Isn't that a 351W ci motor?