White smoke when given throttle

[SemiSweet]

Could be a leaky injector but typically you can hear slight miss or feel a vibration if an injector is dumping to much fuel in a cylinder. Losing coolant? Sounds like a dropped liner. There is lots of info on this topic right on this forum search through the threads.
Get that thing looked at now. Could very well be bad tuning , if so it could be why you had a cracked piston in the old engine.