you can use a 86 D-250 rad for max cooling package.

it is same width but taller, all brass/copper/3 row

it will take it own fan shroud which is all metal for the larger rad core.

I also have had good luck with a replacment rad from napa, it is all brass/copper/3 row stock truck size.

I have a plastic alum rad in my 85 truck from advanced auto, it works ok..it has alum core with single row tubes, but wide flat tubes.

I also use a HD thermo clutch with a 7 blade fanwith the stock shroud.

I have a large 3/4 ton rad in the shed that is new, I will look and see if there is a part # on it.