1995 Toyota Corolla

My 95 toyota corolla was running fine until one day it started to come white smoke like crazy from the exhuast. I thought it might of been the vavle seals that were all busted up that it might of let in antifreeze. I took the head off the engine and had a shop put in new valve seals and resurface it. I put it back together it was okay for a week or so then it started happening again. I took it as the engine crack so I bought a head from the junk yard and had it resurface but never a leak test yet(should of). I put it on but then it still does the same thing. Dont know if both the head are crack because I never had both of the head leak test. I did put on new head gasket both of the time I put it back together. Wonder if anybody could help if I was looking at the right spot or not or is it something else.