Anytime an engine is hot tanked, the bearings will need to be removed from the block. The acid will damage the bearings, plus the chemical reaction with the bearings and acid will hurt the potency of the acid bath, usually making the machine shop unhappy because they now have to replace the acid. If the timing gears appear to be original pieces, they are approaching 50 years of age, and should be replaced. They are machined as a set, and need to be replaced as a set, not just one gear or the other. If you are having a machine shop regrind the crankshaft for you, then they can use a dial bore gage to measure and fit you bearing clearances when they turn it. Plastigage will only tell you what the clearance is at that exact spot where it is, while a dial bore gage can be used to measure the clearances at the parting lines and a full 360° degrees of rotation around the housing bores, much, much more accurate to use a dial bore gage. Are you planning to use new pistons or the old ones. You first will need to see how much the block needs to be honed to clean it up if using the same pistons, you could already have too much cylinder wall clearance and need an overbore and new pistons. If your dead set on reusing the old pistons even if you have too much clearance, you will need to check the deck clearance as you disassemble the engine to determine how much to deck the block. And yes, new rings need to always have a fresh hone to help them seal. But if you still have any ring wear left at the top of the cylinders, the new rings can easily be damaged as they move up and down in the cylinders, so I would advise having a fresh bore as well. Old rings will rarely reseal in a cylinder if they are honed, especially if they have close to 50 years worth of wear on them.
