Engine Gauge Unit (Triple), Type B-7 DC-3 so the angle on the

so the angle on the right side is in fact 180 - 112

which explains why much of the content has a British bent and references the British Royal Air Force and the Air Ministry

The cover appears to have detached and repaired at some point

This 235-page manual contains information on aircraft structure

Engine Gauge Unit (Triple), Type B-7 DC-3 so the angle on theThe WWII era Engine Gauge Unit (aka Triple Gauge), B 7, displayed the performance of 3 engine parameters in one instrument: Oil Temperature, Oil Pressure, and Fuel Pressure. The B 7 unit was used in the US Army Air Force fighters P 38E Lightning, P 40 Warhawk, P 47 Thunderbolt, and P 51 Mustang according to their Maintenance Interchangeability Chart dated Feb 1945, as well as having been used in other military aircraft post war. The serial number