I understand. 76 was very different
74 dash harness would have 2 very heavy gauge wires ( a red and a black ) attached directly onto the amp gauge. 76 has remote shunt design. So small copper traces attach that amp gauge just like the other gauges. Those copper traces cannot carry the full current so if installer did simply put those 2 large wires of a 74 harness in the round connector, that would explain fried traces to amp gauge.