I am back revisiting this topic.
I momentarily considered just buying a low mile 2012-2015 truck just to save some time and effort. Doing that would reset the clock back about 250-280,000 miles but cost me about $19,000 to $25,000.
I like the truck that I have. It isn't easy to find a newer regular cab, short bed in a color that I like. Black, white and all those silver-gray-granite color trucks bore the hell out of me. I don't want a Quad Cab either.
I talked to my Machinist. He is familiar with the 5.7 Hemi so I'm going to look for a good core to have him rebuild for me. If I can get away with a hone and new rings, that would be great. If I have to bore the block, that is fine too. Here in CA, they recently passed some BS legislation that prohibits anyone from installing a "tune" to computer controlled vehicles. If the emission testing guy finds evidence of any non stock tune in the history, they deny the smog certificate. This means I need to keep the engine within the limits of the stock settings. I'd like to use a bigger cam that would provide some improvement without triggering a check engine light or requiring a "tune".
I'm already on board with switching to deeper axle gearing, at least 3.92 but maybe as much as a 4.10. The additional gearing will help with towing as well as making the truck feel more peppy in everyday driving. Also, after 366,000 miles, I'm guessing that the fuel injectors could stand to be douched out. I'm anxious to see how the truck runs with a fresh mill and more gear...