Classic/Antique Car Repair: blue smoke from tailpipe, chevy el camino, piston rings

Question
I am interested in purchasing a 1977 chevy el camino with 305 v8.  The car has a puff of blue smoke from tailpipe.  I was told that the piston O rings needed changing.  From what I have read this is pretty common.  Could there be something else that is wrong with the car to cause this blue smoking, what are some tell tale signs that this may be a bigger problem than old O rings.
Thanks

Answer
A puff of smoke when you goose the engine is usually a sign that there is some engine oil getting by the valve seals. I would recommend that you get a compression test done on the engine to determine the condition of the piston rings and the ability of the engine to hold compression. The valve seal leakage was a common problem in this era Chevy and others and usually can be lived with. The repair is not that difficult and can in most cases be done without removing the cylinder heads.
Good luck.
Brad