brenthamm-
The chevy heater core you are looking at is all copper and brass. Here is a link to it:
Chevy heater core.
It is about 11" high over all BTW. It has a 5/8" and a 3/4" inlet.
I am using the Ford Econoline heater core ($23.00) at Auto Zone. It has both inlets at 5/8" so you can insert a 1/2" barb or solder 1/2" copper fittings right on to it, as I am (will).
Size is almost exactly the same as the Chevy 77 heater core and all brass and copper. I haven't finished my water cooling set up because I have had too much work to do lately. Sucks!
Ford:
Jim