Overhaul...rebuild...reman...These terms mean nothing.
A 1999 L31 Vortec motor is a very nice starting point. Vortec heads, hydraulic roller cam, Chevy's good PM rods, high quality cast crank. Unless it came out of a 3/4 ton it'll be 2 bolt main block but who cares...The crankshaft rear main seal is one piece that slips over the hub at end of the crank.
The most important wear point is the cylinder bores. Cylinder pressure pushes the rings out against the cylinder walls. One would expect to see the bores be tapered, with the bore largest right at the top of ring travel or at least within the first inch. On an older engine the bore might be up to 0.008" larger at the top than at the bottom. There is a max allowable for cylinder wall taper for any engine, you just have to look in something like a Motors Manual. You're probably right on the maximum.
One thing to watch out for with the pistons is if you are just replacing the rings, measure the ring grooves before ordering the rings. There seem to be three separate sets of rings and they don't interchange. Be sure to use the right grit hone for the type of rings you buy. Moly, chrome, steel, cast iron, they all want a particular finish.
The heads have hardened areas for the valve seats and the valve guides should be 11/32 but will be worn. Chrysler factory service manuals used to give a procedure for checking side play and it'd be worth checking that out. If I decide to reuse the heads I like to check the valve seats by hand lapping the valves with a little lapping compound. All I'm looking for is a continuous ring all the way around the seat. I do not believe that hand lap[ping the valves does anything more than that. As the valves expand, they grow more than the valve seat area so the two possibly don't touch. But you can see if there is a burnt area where the seat line should be.
If the rocker arms don't look too worn you may want to replace only the rocker balls with grooved balls.
The camshaft is 191/195 on a 111 LSA and should be adequate. Try to keep the lifters in the same configuration as when they come out.
I use carb cleaner to get the varnish off the crankcase walls.
I bet the crank is OK but judging from past experiences I'd say stick a new oil pump into that engine. Unless there was detonation, which will show as wear on the upper bearing half, the lower rod bearing halves will show the wear and the crank throw should be measured top to bottom. That's the most important.
R.
