The heater in my 77 always blew hot regardless of where I put the temperature slider and I tracked the problem down to a faulty water **** valve under the dash. I had the capillary style valve (http://www.classiczcars.com/forums/thread46448.html) and spent a little time looking into a direct replacement, but after spending that kind of "quality time" working under the dash, I decided that I never wanted to go through that again. So I changed over to a ubiquitous newer style water control valve w