The Stovebolt Site Forums The Shop Area Engine Shop engine diagnosis

I had a gentleman approach me about fixing his '66 F*** p/u for him (ya, I know, I'll sanitize my tools and shop afterwards) anyways, we started it up and it has real loud valve train rattle and lots of smoke coming out from the oil filler on the rocker arm cover and some smoke out of the tail pipe. I drove it to my place (shop) 30 miles and you couldn't see behind me for miles. There is so much pressure in the crank case that it was spewing oil all over the engine out of the rocker cover. Prognosis? I think, from the looks of things that someone in the not to distant past has done some head work and a valve or something has gone through a piston, but there is no popping or back-firing. Have prepared him for the worst case scenario, getting a different engine, but hope it is only a hole in a piston. I haven't opened the engine up but will soon, anyone want to try to diagnosis this before I pull it apart just to see how close you are?