Sounds like you blew the headgasket, white-smoke is generally steam produced from the water in the water jacket around your cylinders leaks into the cylinder itself. Something you need to be careful about with these aluminum blocks, they don't take kindly to ridiculous cylinders pressures produced when dry-revving the engine at that RPM. Also probably compounded by the fact that you didn't let any of the new parts seat during the break-in process (Yes, there's a break-in period which varies from 500-2000 miles once an engine has been rebuilt).