1.5 is perfect, broke in engine.
This will center the lifter plunger in the middle of the lifter.
Unfortunatly everyone has a different value for zero lash. Zero lash is where there is no vertical play or slop in the push rod. At that point 1.5 turns is perfect.
Now some folks determine zero lash where the push rod meets resistance while turning or twisting it. I have tried 3/4 turn in this case but did not have good results.
Part of the difficulty also results from not being able ot see the lifters themselves due to the lower intake in place.
Paul Prince, you have the easy method of adjusting the lash. Mine came out perfect with that technique. I went the 1.5 turns and engine is very smooth, powerfull and alot quieter than the 3/4 turn I had originaly went with.
Valve lash is a can of worm subjects. There are so many variables, technique, wear, mileage and results. 3/4 turn works for some but 1.5 has worked for me.
Silver 86 SE 2M6 4-speed, with "check wallet light"