That's an impossible situation on stock E7s.

Did you put that cylinder to TDC, make sure the valves were not open/opening?

2-3 turns would have surely stripped the threads or broken the bolt from zero lash.

2-3 turns, assuming 20 threads per inch, means they tightened another .1-.15" or 1/10th to 15/100ths.
2-1/2 turns would be bang on 1/8".

My guess is your not torqueing the rockers correctly, or do not have that cylinders rockers at TDC when your torqueing them.

 

I'd be tempted to get a dial indictor, pull your valve cover and spark plugs, verify cam lift at each rocker turning the engine over by hand.
Maybe you've got a flattened cam lobe.