2022 and up possibly alternator upgrade

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So let's start out by first saying great job GM on the sabotage by making it so we cannot install an upgraded size alternator on our engines without extreme modification. The pre-refresh models had the water pump setup so the factory belt would run off a stretch belt but you had the recessed hole and threaded holes for installing an automatic tensioner and idler pulley like the 6.6L has for the drive belt. My 2023 comes from the factory with the bolt hole and recessed hole on the water pump along with the single bolt hole for the second idler pulley next to the tensioner are plugged up. It looks like GM inserted a metal plug into the recessed hole and threaded in a bolt and shaved the heads off where the tensioner and idler bolt up to the water pump.

 

So with that the Mechman 370A Elite alternator I had on my 2014 Silverado 5.3L will likely not work without extreme modification. My options are to replace the water pump assembly and buy a tensioner, idler pulley and belt for converting the engine from the stretch belt to an automatic tensioner setup OR mess with the pulleys and find one to keep the same size overall and retain the factory stretch belt.

 

My question for others is what size was the idler pulley on the drivers side of the engine and what size is the factory alternator pulley? I found other posts saying the OEM alternator pulley is 55mm and their Mechman alternator came with a 46mm pulley but I want to make sure that was the case. My alternator has a 1.75" pulley from mechman and after talking with Mechman my options are to either replace the water pump and modify the engine to run off an automatic tensioner or trade in the alternator for a brand new one at 30% back towards a 400A alt that works with the stretch belt from the factory.

 

Has anyone found a replacement for the idler pulley on the drivers side that is larger in diameter to help account for the loss in size of the upgraded alternator pulley? I still have the belt on but when I measured the size of the OEM 170A alternator pulley with the outer lip it is 2.5" and if I get that size of pulley for the mechman I was advised that the alternator will die at idle since it's spinning too slow to self excite.

 

Are there any other places to source a smaller stretch belt? I ran a gates belt on my 2014 but they don't even carry a OEM size stretch belt for my 2023.