I have a 95 z with just the bolt on's and some comp 1.6 rockers.

Which is the best adjustment

GM said 1 full turn,however everyone else seem to think 1/4 to 1/2 turn.

I have even heard 1 full turn then back off 1/4 turn which one is right

I know the factory ones are 1 full turn,GM techs let me hear from you.

 

http://web.camaross.com/forums/showthread.php?t=508981

Less is better.

 

If less is better then why does GM adjust them 1 full turn

 

So they will stay in an acceptable range of adjustment for a long time. They also do not set them from a "performance" point of view, like people here do.

 

How much HP will be loss between 1/2 and 1 full turn

 

I would say it is nearly impossible to estimate.