Amp meter pegged

71 duster, came with a slant six but now has a junkyard 360 in it

When I dropped the 360 in it almost a decade ago in probably put a new alternator in there

A few days ago while driving my radio cut out and my oil pressure gauge went dead

I've since notice when this happens the amp meter also pegs past +40

At Idlw it sits close to dead center but as soon as it gets a few rpms on her the amps shoot way up...what's going on here ?

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