Yes, you can replace the pressure line with copper and a T to run both gauges at the same time. But then you'd have to deal with Segal's Law.What pressure does the add-on gauge show at highway speeds? Does your '53 still have a spash-oiled 216 engine or a full pressure 235? Big difference.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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