Heres what I have. I need a heater core whose dimensions of the core itself are 7 7/8 x 2 1/2 x 7 3/4. I do not care about the tanks. I will be soldering on different ones. Heres the kicker.... They cannot be aluminum (because I have not figured out how to solder to that) and they need to be cheap. I have been looking for a while and no luck. I have seen cores for like 80s pickups for instance in the 20 -30 dollar range which would be great. If you are bored HAVE AT IT!!!! THANKS!!
Believe it or not, I found a comprehensive list of heater cores on a site for high-performance computers. They apparently use them to cool off "hot" computers. It's a spreadsheet, two of them actually, one tells all the dimensions, the other cross-references from the FEDCO model number to a make and model of car that it's used on.
There are lots of them near the size you want, none exactly the same, and most are thinner (which may not be a problem). I'll send you the native XLS's off-line.