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 gauge. You probably want a 0-200 psi, liquid filled, tattle tale gage. I was told McMaster has them. McMaster is a large gauge 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 gauge 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 gauge to the engine. Let it hang loose so that engine vibrations will not destroy it.