Well, can't find that old core right now. I'd say your best bet would be to try find an old heater box you can scavenge parts from, could probably pull the oring adapter off the other line and install on yours. It's gotta be a whole lot easier to assemble everything if you can install the exterior lines by sliding them in after the box is assembled and mounted. That would also be a good way to find that connecting link that operates the bypass valve. Good luck with it. Mike
