Toyota Repair: white smoke from exhuast, white smoke, cly

Question
92 toy camery 6 cly auto,  the mechanic replased the trans,the car was ruing great for a couple of days and it just started blowing white smoke from exhaust did not overheat,but mechanic said it had blown headgasket, replaced it resurface the heads change spark plugs,put everthing together and stil has problems blows white smoke and gas  please help

Answer
After replacing the headgasket it can take quite a while for all the coolant to clear out of the exhaust and it may smoke for a while, how long was the engine run after the gaskets were replaced? It may take up to an hour of driving to clear the exhaust out.