Ammeter burnt out should I replace?

You have several ways of looking at this

1--Very heavy loads going through the ammeter is the basis of the problem with these cars, which is exactly what we are curing by doing things like bypassing the ammeter and using a voltmeter, or improving ammeter wiring

2--For the ammeter to "read correctly" all loads must be on the AMMETER side fo the ammeter, rather than the battery. This means that if you have loads -- fans, pumps, or landing lights -- hooked up to the starter relay battery stud or the battery, the ammeter, even though it should be "centered" with the battery up, will in fact show "charge" with one of these heavy loads on

3--So if you are willing to put up with incorrect readings during the use of heavy loads, you COULD hook them to the battery source rather than the ammeter.

The entire problem is that the

wiring for the charging line and battery feed are too small, and always was

the bulkhead connector terminals was never designed for that kind of current

the ammeter itself is limited for current capability