I've spent the last couple weeks making some headway on the 60 teardown. Upon removing the valve cover, rockers, and push rods, I was able to pull the cylinder head and see what kind of mess was waiting inside the bores. Each cylinder was filled with mouse crap, rust, and tar buildup from sitting so many years (and having been run an additional 6000 hours since the first rebuild in 1971). Cleaning the cylinders out revealed minor scoring on the walls and some pitting, which weren't too surprising given the circumstances. Out of curiosity, I pulled the governor housing and placed a 4x4 wood block inside the #1 cylinder. I hit it a few times with a dead blow hammer, which was enough to get the piston moving and break the engine free! I then repeated the process on the #2 cylinder and kept switching back and forth until the crankshaft, pistons, and rods were able to move (somewhat) freely again. Evidently, the cylinders were not as "stuck" as we had initially thought!
When separating the frame casting from the chassis, the engine block had started to split away from the main case. I used the loader to remove the frame casting, then immediately pulled the rod caps and removed the block from the chassis. The #1 piston and rod broke free, but the #2 piston was stuck inside the block and required hammering it out once the block was removed. Upon closer inspection, the crankshaft journals showed some scoring and will need to be turned. After removing the clutch driver with a homemade puller, then removing the pulley, clutch fork assembly, and first reduction gear housing, and tapping on the crankshaft at both ends, I got the main bearing retainers loose and was able to remove the crankshaft. I then took the block, pistons/rods, head, and crankshaft to the local machine shop to be thoroughly cleaned and checked - I am currently waiting to hear back from them regarding how much the crank will need to be turned down, and how far out the block will need to be bored. I am hoping it won't need to be bored wider than .045" so I can rebuild it again in the future if need be. Currently looking for a new set of high-compression M&W-style aluminum pistons that are American-made, but supply seems to be an issue across all vendors right now, so I might be stuck for a while until they return to stock.
After the crankshaft was removed, I pulled the cam and cam follower assembly, and began the never-ending process of flushing 2.5" of sludge and mud out of the bottom of the crankcase (what a mess)...thanks to the advice of Shane, I made a tool to pull the oil filter housing neck/outlet out from the bottom of the crankcase, which worked very well, and then proceeded to remove the oil pressure regulator, lines, and oil pump. These will need to be thoroughly cleaned and rebuilt and I still need to flush the rest of the debris out of the crankcase before it's ready for a Glyptal coating. Having broken one of the three starter mounting bolts off a few years ago when working on the tractor outside, my only option to remove the starter was to hammer it out. It was full of mud and rodent nests due to its exposure to the elements (sitting in the bottom of the tractor over mud with no cover), so it is most likely beyond saving.
I also removed the drawbar assembly (which already had two broken bolts inside the bottom of the final drive housing), and am hoping I can cut off the ugly bracing that was added to it years ago - I'd like to try and reuse the original drawbar if I can save it without cutting away too much material. It's been heat-treated many times in the past (due to welding/torching/cutting), so I have to be careful how far I go with it. I removed the Powr-Trol hydraulic valve assembly as well - like many of these tractors that lived outside, the rusted-out battery box over the years allowed moisture to get down inside the top cover of the valve, and as a result it was full of rust. So it will need to be thoroughly disassembled and cleaned up.
While I wait for the machine shop to get to work on the engine components (sometime within the next month), I plan to continue with the teardown of the transmission, final drive, and PTO. My goal is to have the tractor completely stripped down by the end of this year so I can begin cleanup, wire wheeling, and primer on certain parts. Also trying to build up the patience to get the rear wheel wedges broken loose and get the wheels slid off the axle shafts - that's going to take a lot of time, heat, and penetrating oil, but I'm confident that we can get those wheels off. Everything else I've removed or taken apart on this tractor has been pretty straightforward so far.