My 64 W/a 352FE with 57000 original miles has started smoking more and more. Sends a blue cloud(small) when pulling up to intersections and accellerating away from a stop. It's been getting worse, but it smokes while just idling as well. Did a compression test with the engine warm and the compression was between 119 and 132lbs on cylinders 1-8. My manual says suppossed to be between 160-200. Mechanic says time to rebuild the engine. Does it sound like bad valve guide seals or time to rebuild it.