What size wrenches are used to set these and does anyone know the bolt size and thread?
The wrench size is 7/16.
On the lifters with lock nuts you need a very thin wrench and a regular one.
I found a nice long, thin 11 mm open end wrench that I touched up with a small flat file that works nicely.
You hold the lifter with the thin one, turn the bolt to get the right clearance plus one thousandth.
Then tighten the nut down with the thicker wrench.
When you tighten the nut it will pull the bolt up out of the lifter a little, about .001”.
I shoot for 010” clearance. If I end up with.006 to .010 on the
intakes I leave them alone.
If I end up with .008 to .o11” on the exhaust I leave them that way.
You can set them anywhere from .006 to .012 and they will be just fine....and quiet enough for an old four banger.