I dont think you would need to go all out for new heads, but you'll need to take them out, take them to a machine shop and get them to do a compression test on it. I would guess that you DO NOT need new heads, they just needs to be resurfaced. Unless they're cracked, then you will need new ones. And I'm sure the machine shop would suggest the resurfacing too because they want your business, lol.

Clean those heads up real good, get them looked at and get new heads/resurfacing (whatever you decide), get new gaskets and you're good to go.

Also, this may be a good time to start looking at the cooling components of your engine. There is a reason your truck started all this in the first place. Could it be that it got hot? thermostat not working properly? water pump still pumping? radiator clean, working? Or maybe the gaskets were just getting old? You know the regular stuff. The last thing you want is to get this work done and it get hot on ya again and crack or warp another head.

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1992 Ford Ranger XLT 4x4 2.3 4cyl 5-speed