Message: in your 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.
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. Many do not firmly connect the gage to the engine. It is left hanging loose so that engine vibrations will not destroy it.