My wife keeps a cloth on tunnel under dash of our SPF 1547 to use as needed. This summer, we noticed cloth was "damp" and "oily" and thought liquid was coming from
oil pressure hose. I pulled speedo, checked hose and it appeared to be intact. I added this to list of things to be checked when I took car to Olthoff Racing for it's annual "look over". After investigation, Dennis informed me the leak actually was coming from heater core and alas he could not source one for me. He had two old ones but they both had leaks. After discussion, we decided best thing to do for short term would be to bypass heater core and prevent leaks. So, leak fixed but no heater.