Just bought a 56 Belair with 235 and powerglide (original). Car runs quiet, smooth and strong around town. If I get on the highway for more than 5 mins, one valve starts ticking loud. Get off the highway and the ticking quits within a minute. Engine was rebuilt 20 years ago and is pretty clean inside, no sludge. I pulled the valve cover and have oil weeping from all rockers. I don't think the engine is overheating (gauge is not working), it can be shut off and started right back up without hesitation. Other than this intermittent tick, the engine is great, no smoking or other weird noises. Any clue to what's causing this? My original thought was that sludge was preventing the oil from draining back quick enough and the valves were starving for oil. Doesn't have an oil gauge, only a light and it remains off when the ticking starts.
