On another front, I bought a big (30") truck motor recently. I was concerned that if I had to go through it I'd never find bearings for it. He told me if I tear it down to take real good care of the inserts, they can send them off, have them re-coated with babbitt, then line bore it and salvage everything. I had no idea you could do this.
I have found out these big 7 main engines use heavier duty bearings. They are copper-alloy lined with a lead-tin overplate. They are not babbit lined as on the regular flathead 230/251 or 265 engines. Will the soft babbit hold up if you push it? Thats what has held me up on doing one of these engines. I have driven these big blocks a lot and you do need to push them on the hills even with a 2 speed rear end. I'd hate to hear a knock after a quality rebuild. All I have been able to find is babbit overlays being done. Finding any engine parts is really tough. Most all the parts need to be special made=$$$. Egge/ Terrill machine ect. Pistons and ring groove spacing is an issue too. The OE pistons are a H-duty steel strut design piston. Custom forged pistons are the only way to go being a custom order. I have found over the years MoPar rings/gaskets/ 1 piston and rods and mains for the 377 and smaller engines but no parts for the 413 which uses bigger rod bearings and pistons and has the hydraulic camshaft.
Bob