Should I get an anuminum radiator?

[Chevy454]

I talked to a guy at a local show a couple weeks ago, and his father-in-law had a 440 or 383 Cuda that saw street duty...over drive trans, vintage air, that kinda thing...anyway, it was running just a *tad* warm, so he called up some parts place, and they sold him an entire system and guaranteed it would drop the temp by a bunch of degrees...dropped like 2-grand to this place...aluminum rad, water pump, lines, all kinds of crap. Well, guess what? The thing runs *hotter* now! Needless to say, the guy isn't happy, and last I knew he was trying to return the parts to no avail...