White Smoke from the Exhaust Pipe Near Engine Block

Just finished installing a recently rodded-out radiator, a new water pump, new transmission fluid filter and fluid, and added two gallons of coolant. Given, the car has sat for nearly 2 months, what could be the issue here? Temp gauge reading below average and I double checked my belts to make sure they weren’t rubbing. Any guesses from the pros? I’m pretty well stumped. Afraid to get it down the road.