RE: AquaCraft U-18 Miss Vegas Hydro Thread_Make it Fast!
because of the head shape at the squish band, plastigage is not very accurate at that tight of a gap (FYI a piece of notebook paper is Approximately .0035" to .004"in just for reference) a good set of Calipers and some Small Solder works a Little better.
The Squish band on the head Looks Almost Flat but is is actually tapered somewhere around 3* degrees the very outer edge of the squish band is your Tight area and where you want to set clearance.
bend the end of the solder so it will go in the glow plug hole and the tip will touch the side of the cylinder wall, then turn the crank over a couple times to squish the solder, remove it and measure the tip with the callipers.