These old carbs will sweat condensation when they are cold running. 1st check to make next time is to find out whether it's water vapor or fuel. A simple smell test will tell you.
It could have also been a loose connection of the fuel line that you may have corrected when you R&R'ed it.
3rd swag is that fuel may have leaked out from around the throttle shaft. This is common in worn out carbs. If it isn't sucking air (as in a vacuum leak) it's not too serious yet.
Smoke/vapor from the valve cover is probably piston blowby which is common in high mileage engines. As the rings/cylinders wear and the engine consumes more oil vapors, these increased combustion byproducts that normally escape through the draft tube will make their way up to the head through various passages and out the vents. Sometimes as an engine is ran more the blowby can decrease (as was the case in my 49 216) but it will not completely go away as the engine is worn past the point of no return. Normally if the blowby decreases as the engine runs don't worry too much about it. But a rebuild is in it's future.
These old engines can get alittle cranky to get going when cold. I use the following to get mine going.
1) floor the gas pedal to get a good squirt of fuel in the manifold.
2) fully close the choke.
3) set my home made fast idle setter on the hand throttle knob to get the engine to run at a faster rpm than what the std fast idle circuit provides on a Rochester B carb.
4) turn key on and depress the stomp starter, once it starts immediately open the choke and let it warm for a few minutes at fast idle, then remove the home made fast idler from the hand throttle knob. It will still idle slower than when warmed up but it won't stall. If it acts like it's going to stall I will manually keep the rpm up at idle.
If it doesn't start at 1st using the above, it takes an enormous amount of fuel and cranking to get it going. But thankfully it usually starts right up within a couple secs of cranking, even on the coldest days in which case I pump the gas pedal 2 times
Good luck
Dave
