Should I swap my 2.0 or replace the rings?

I have a 84 b2000 with the stock 2.0 on it. I replaced the head gasket in it about 6 months ago, but now im pretty sure I blew a piston ring. Im planning on getting a new motor for it, but im not sure what motor I should get. My plan right now is to find a 2.2 to throw in it, but if that wont make a big difference performance wise, id rather just put new piston rings in the 2.0. The motor has almost 300k and I drove it like it was a rally truck haha. So any suggestions?

Well, the Mazda 2.2 engine is not really going to give you any more power than the 2.0 already does, so you may want to just get a new motor ready to drop in it. Don't know what kind of horsepower you have in mind, but if you deviate away from a 4 cyl. Mazda engine, there will be a bit of fab work involved.......not only with just the motor, but a trans also.

I did a 4.3 GM Vortec and automastic transmission (add shift kit) from a truck [do not use van, a/c and alternator too high(I have that engine too)] install. Engine must be serpentine, single belt, with flex fan, no spacer.
Changes to the '90 model; none, used stock radiator, you will need to get a thicker/bigger one, like from a later 2.6?
I made the engine (mount on the Mazda original mount welded in pads)/transmission mounts used Mazda throttle cable. I modified the original automatic shifter and used it. Power steering, if you change yours to power steering, is right there by the steering sector, or you can pull it off.
I used a pickup or Astrovan lower hose, cut in two with a pipe going under the crank pulley (lower radiator inlet is on opposite side from engine), for when the belt breaks and slings.
Exhaust manifold on driver's side takes a little design work, no big deal.
I am not sure about yours, the heater core on mine is immediately behind the firewall, dead center, so no cutting the firewall out for a v8 and requires much engineering out front for that other two cylinders.
Results, according to your engine build, 180-? horsepower. Standard transmission would probably work out fine if you go that way, just more stress on the rearend, chirping into 4th (5th) You do have to make/have made the drive shaft, and of course, exhaust of choice.
You are not in one of the ridged emission control states, like CA.? If so, just forget everything typed here.

A B2200 2.2 engine will need modifications, as will a 1986-1987 B2000 engine. So I vote to re-ring the existing engine, likely you could do this without removing the engine.