Bill wrote:
here are some photos, please be sure to put the whole link on one line
so you actually arrive at the destination:

http://i1171.photobucket.com/albums/...ercoreback.jpg

http://i1171.photobucket.com/albums/...rcorefront.jpg

whatever these fit, it hasn't been made in many years, brass castings
like that were uncommon even by the 50s.

Looks more like a radiator for a small engine than a heater core.
Something along the lines of a Hart-Parr or similar

--
Steve W.