Message: in your fuel injection book, you show a vacuum gauge with a telltale,
do you know where to obtain one of these gauges? KS

It is not a vacuum gage but a pressure gage. You probably
want a 0-200 psi, liquid filled, tattle tale gage. I was told
McMaster has them. McMaster is a large gage supplier.
I did a web search a while back and was able to locate them. I do
not have any further info from that.
In addition, locate the gage connection after the barrel valve to get
the injector pressure after the bypasses and the pump relief
pressure. You can tie into any extra port in the distribution block
or tap into the block if no added ports are available. Also do not
firmly connect the gage to the engine. Let it hang loose so that
engine vibrations will not destroy it.