Where to find a new replacement radiator for a 1973 Duster?

I bought a Spectra CU526, from SummitRacing, back in March of 2019 (for $177.99). I haven't had any issues with it. This is on my '71 Dart GT relatively fresh stock rebuilt 318, 4-bbl, auto, MP Viscous Fan, and factory shroud.

Fresh Pass Side.JPEG