I have just aquired a 1964 Impala with the stock 283 and only 39,000 original miles. I noticed a lot of oil build up that I thought would have come from seals leaking. I tuned up the motor and took it for drive (about 25 miles rnd trip). It seemed fine outside of blowing black smoke out the tail pipe when I accerated (figured it was carbon being blown out). When I parked it I noticed light smoke from the motor. When I investigated I found that the breather cap was push up at an angle and oil was all over the engine bay. Does anyone have any ideas as to the cause. I plan on doing a compression check, should I do something else?

Thanks!