car runs great but smokes......

[7spokenightmare]

i have a 97 240sx se with the ka24de stock motor and stock auto transmission. if i rev it up past about 3500 it blows smoke out the tailpipe. the car runs awesome otherwise, that is the only issue.... its using oil, about a quart every two weeks or so. im not getting oil in my coolant and it isnt sputtering or trying to die... it makes decent power throughout the rpm range and i do tend to enjoy getting it up in the higher rpms quite often and have had the problem since i bought it about 4 months ago. it isnt getting any worse either.

i think its blown piston rings, but im not up on a lot of the stuff down in the block... ive mostly worked on the head or above on all my cars

anybody want to tell me if i got it right? or something else i need to check to confirm?