I picked up my 84 C20 Burb today! I'm mostly pleased but it does have a couple of quirks. 1) It'll start great when cold. Wait for the glo plug light to go out, and fires up no problem. When I stopped for fuel, and later for a coffee, it wouldn't start for some time. The first time it had me baffled - I looked under the hood and underneath. After 20 mins or so I tried again - this time the glo plugs cycled, and it started right up. Then later after my coffee, I noticed the glo plugs didn't cycle, and it wouldn't start. I popped the hood (I was in the shade this time) and after 10 minutes, the glo plugs would cycle, and it started fine. Is there some kind of thermostat that checks the engine temp and decides if cycling the glo plugs is necessary? Can it be calibrated? How about a manual control for the glo plugs? 2) I also have a drip coming from a rectangular box on the firewall (fuel filter?) It looks like a complex piece though... what does it do exactly? Can it be replaced with one of those commercial-type spin-on units?