I replaced the heater core in my 80 (with A/C) 15 years ago. I noticed a few drips out of the heater box last October and immediately built a heater core bypass. (Seemed to drip only after I shut it down and never fogged the windows or anything. Tiny leak now but I know how quickly it can become a major issue on a cool day.) I'm noticing most of the available heater cores out there are aluminum. (NPD still carries a copper/brass one) Realizing that differences in metals potentially cause corrosion within the heating/cooling system... I still have iron block/heads but now have an aluminum intake and radiator... Would there be less galvanic action by also using an aluminum heater core? I don't remember electro-chemistry well enough to know if the copper or the aluminum is becoming the sacrificial metal in this combination but eliminating one of the metals would help... Wouldn't it? Has anyone here had an aluminum heater core in their car for over a decade? Or... Should I just go with the copper one and hope it lasts another 15 years? (I'll be over 70 by then so I'll need to get my middle-aged sons to help change that one. ) BTW... I plan to connect the new core to by bypass hoses and pressure test it prior to any disassembly.