OK, thanks. I'm going to get a seal kit and try it on my old valve. I also did some more checking and found the Gates 20662 hose.
It's a 5/8"x3/4" bypass hose that looks like it will take care of the problem of different connection sizes between the heater core and replacement valves.

Last edited by Kojack; 02/18/2011 3:53 PM.