The way an Amp meter and a Volt meter connect into the wiring is Not the same.
https://www.autometer.com/blog/faq-p...or-an-ammeter/
Not knowing how the car is wired now makes sight-unseen suggestions fairly difficult.
Disconnect the battery first.
Going out on a limb here but, in general... If the Amp meter has (only) two relatively large wires connected to it (excluding a panel light) those large wires could/should be connected together once the Amp gauge is removed.
Depending on how the existing wiring is run, it may be helpful to remove or bypass any extra length or unnecessary connections in those wires. (less to go wrong in the future)
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