I don't understand which of the two pictures is the current state of your wiring.
The first picture shows an appropriate number of wires on the ammeter, but no voltage reducer on the gas gauge.
The second picture has the reducer, but is missing the large wire on the ammeter, which according to bartamos' wiring diagram provides battery voltage to the ammeter.
I am assuming you have the small wire (feeds the horn) on the "hot" side of the ammeter as shown in the wiring diagram.
'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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