ive been burning my oil

not entirly sure what it can be. just rebuilt my bottom end so rings are new and have prolly put 2000 on it since i put it in. i only see smoke on start up and upper rpms say 4,500 or so. some of my friends say my rings could have not set right, and i read if it were rings it would be more constant smoke? my head has never been touched, but has new seals. i have been running lean so i guess its possible that the seals could have worn. im not sure. ive done compression tests and got around 200 on all 4. i want to get a new head, but it is quite pricey to just take a chance with. any one got any suggestions as to what i can do?