White smoke from exhaust

It has dual exhaust and it is coming out of both. It has a rebuilt 350 in it (do not know who rebuilt it), and was overheating until two things were done to it; belt alignment, and a mechanic adjusted the carburetor (without asking). The white smoke was not happening until I picked the truck up from the shop, and seems to get worse as I drive. The coolant seems to be not circulating properly as the bottom of the brand new radiator is not hot after an hour of driving, but the top is. The heat is not working either. Now on blown head gaskets, the truck runs fine, the oil is good and at the same level as when I bought it, coolant is not bubbling and looks good, spark plugs were pulled and look good, checked for exhaust gases with a chemical tester twice and nothing. All of the hoses heat up as well once it runs a while. Really left us all scratching our heads.