[BVR421]

seth, they are hydraulic lifters, they do not run any positive clearance at all. Assuming an all original Pontiac valve train, when the nuts are tightened down to 20ft lbs the lifer is at about half its travel. When aftermarket cams are installed the geometry changes and different locking arrangemnts have to be made and the procedure is more like adjusting hydraulics on a chevy ie the slack is removed and a further half turn sets the preload on the lifter. Obviously the factory nusts wont hold so a simple solution is to use chevy locknts. That senario is possibly where you here of "adjusting" the valves. Either that or in a race motor if a solid lifter cam is installed then the valves need about .020+ clearance adjusted into the valvetrain. Hows that for a longwinded explanation? If there is not a problem with yours, dont screw around with them. No offence meant but by your questions you seem a little vague on how it all works and I would not advise messing with the valves at all based on that. Misadjusted vakves can cause a lot of expensive damage. (8--( Again, I hope you take what I say as well meaning advice. I had to learn from scratch as well. A MOTORS or Chilton manual that covers your car would be good reading.