I believe you can replace it, but I and a lot of other people put it on in addition to the stock wire

Exactamundo! You can do either, I took mine out, just to save on clutter.

Also, 1/0 is a lot bigger wire than needed, I have access to it cheap is the only reason I'm using it. If you keep the existing wiring, you don't need to run as large of wire as it will have 2 paths to follow.

I have 2/0 on mine and my charging system shows 14.3 volts at idle

My Blazer shows over 14v at idle with everything on now, and it still has stock wiring. This is the second step toward a winch. First was the 78 series dual post AGM, next will be the 145A alternator, then the winch.

I'm using the ad244 off a Yukon with 2/0 wire without the factory wiring with the same size battery as stock, but its a top post, and I'm catching 14.7 at the battery with everything on

I'm running 14.7 (Might even be a little over 15) with a new alternator, stock wiring also. Def. interested in the lengths and eyes. I'm really wanting to do this soon.

My readings are with a volt meter at the battery, not the way off gauge on the dash

Yup, never trust that damn gauge, always always always check with a voltmeter

big 3 made no difference lights still dim as they did be4 with stock wiring with everything on gonna look into a bigger alternator anyone have any suggestions?