Ford Repair: too much blow by, ford f 250, compression ring

Question
i have a 1996 ford f-250 460 7.5L 3/4 ton pickup. it runs just fine but it burns oil bad and its coming out of the hole just below the oil cap in the valve cover. there is a hose attached to that hole and the hose hooks up to my k and n air cleaner. the smoke is coming out of the hose. i checked the pcv valve and it rattles so it is good. my thought it is either a valve or compression ring. i ran an compression test on it and one cylinder only read 20lbs and the other 7 read 125lbs. whats your thoughts?

Answer
how many miles on this vehicle if over 150k time for a rebuild-probably valve guides and valve problems-could have ring problems either way 20lbs is major problem. if the truck is in great condition body and trans wise put a good rebuilt engine in it.