i've got an 87 k10 350/700r4/208. upon acceleration from sitting at a stop light i get a cloud of smoke. at first i thought "new valve seals" would do the trick however i pulled the tbi unit to clean it, replace the injectors i noticed oil looked like it was coming through the pcv valve into the intake causing the smoke. could this be from a vacuum leak, valve seals being bad or ?. i did a search and found a lot of good info. but nothing exact. any ideas would be appreciated. i never did have the heads service yet.