I have a BNIB dc 270 sp alternator
And a used dual alt bracket used less than a year.
They fit most GM vehicles
This one was bought for my Tahoe with a 5.3
$424 shipped for the alt
$200 shipped for the bracket.
My dc just went out, kinda like yours. It wa charging at 14.4 now it's more like 12.5, just mailed it back to them today. Had to call them and get a rma number to send it back.