xbox - If you're considering an all-aluminum radiator, look at the Liland 188AA:
https://www.carparts.com/search?q=Liland_188aa&itemperpage=15&vehicle[year]=1988&vehicle[make]=Dodge&vehicle[model]=Ram_50&vehicle[submodel]=Custom&vehicle[cylinders]=4&vehicle[liter]=2%2E6

I've had one for four years with no issues. Except for needing a longer overflow hose and a new, smaller cap, it was a perfect swap. I think it will fit your '86 because I had an 86 rad in my '88 until I hit a deer, and the '86 rad fit without modifications. Measure the distance between the mounting bolts. If the centers are ~25-1/4" apart, the 188AA will fit.

Another radiator with near identical core dimensions to the Liland is this:
https://www.jegs.com/i/Champion+Cool...SABEgIPnPD_BwE

It's a touch narrower so you may need to modify the mounting brackets and change hoses to accommodate the horizontal and larger inlet and outlet diameters, but it looks like a promising option.

Other possibilities are radiators for a 1966 Chevelle;
https://speedcooling.com/product/196...inum-radiator/

and 1972-86 Jeep CJ with a V8 Chevy conversion; for example:
https://www.ebay.com/itm/30363465620...evt=1&mkcid=28

Both have cores one or so inches larger, horizontal outlets and larger hose diameters, so installation will require some effort.