I just had the heads serviced and I can only get compression when the rocker arm nuts are loosened less than zero lag. I have full compression when the nuts are loose, but when I tighten them any more than finger tight I lose all compression. This is only accruing on the number one cylinder. I think the lifters are stuck but I am not sure. The valves have a positive stop on the rocker arm studs. Any help would be greatly appreciated.