Well A caliper from a machine shop will look like an F when open some, It is a measuing tool. You can buy cheap ones
from harbor frieght or sometimes stores. one of the funtions they do is a metal rod pokes out the bottom of it
as you open it and the amount it is open up at the jaws
is the same as this rod protrudes from the bottom, so you
can use it as a depth guage, (Not accurate to the thous, but it works.) The other way to improvise one is drill a 1/8"
hole in a block of hard wood and then put a 1/8" dowel
with a rounded tip into the hole and use that as your guage.
With my booster, It seemed to work fine, Made a squanking sound once in awhile. I swapped the one in from the parts truck (Cleaned it and painted it) and it works much better.
87' Zook Spoa,M/L 33's, 4.16 tcase,4.62 gears Camo,Header,2"exhuast, Cam.
Lockers, 8klb winch, -Wildweasel2 NE4WI- club http://www.cs.umass.edu/~glenn/personal.html