With a lot of help from Mike Tiberio over the internet, I was able to determine:
My pistons were originally designed for an 850 T/850 T3. The previous owner had remembered them being 850 Le Mans pistons and he had added a spacer between two base gaskets to provide sufficient clearance. I no longer have to worry about that...nor about trying to get 850 Le Mans pistons to work well with small valve heads.
My block is from an 850. This is a good thing as I wanted the 850 cc cylinders to have a slide-in fit into the case with the proper case-cylinder clearance.
Correction (): I later learned that my eninge block is the original block from the V1000 I-Convert. While I was using the 850 T/850 T3 pistons and cylinders, there was too much clearance between the engine case and the cylinder. I am now running Gilardoni 1000 cc piston and cylinders with the correct clearance.
This means that somewhere along the way, the original convert engine was replaced with an engine from an 850. Probably an 850 T3.
Correction (): Only the pistons and cylinders were replaced. The crankcase and crankshaft were the originals from the V1000 I-Convert. In addition to being down on power, the 850 cc pistons were not the proper weight for the V1000 I-Convert crankshaft. This caused undue vibration that was remedied when I installed Gilardoni 1000 cc pistons and cylinders.
Both master cylinders were mostly dry (just a little damp brake fluid residue left in them). I filled them up and did a quick bleed of the brakes. Some pistons work fine, others are pretty stiff, and I've got a leak where the hose connects to the rear master cylinder (that explains the missing paint on the frame in that location much better than battery acid). These will need some work. Brakes cannot simply stay good without being used regularly.
Pulled the rear wheel. Splines look good.
Pulled the rear drive. There was silicone goop between the swing arm and the rear drive. The silicone goop was dangerously close to getting in the rear pinion bearing, but seems to have been spared that fate. I removed the pinion carrier and the pinion teeth look fantastic! I am very pleased the rear drive isn't trash.
Pulled the front wheel and front fender.
Removed the swing arm. U-Joint is in perfect condition.
Drained as much ATF fluid as I could from the lines and reservoir.
Removed the frame. I used the crabbing technique to do this. This was my first attempt at crabbing a Tonti frame. For the most part, it went rather well. It did get a little dicey when I removed the frame from the engine/transmission. But, no damage to any parts :>
Separated the engine from the transmission and drained the oil from the torque converter.
At this point, the garage is a bloody mess. ATF fluid everywhere from spills. I've not had this messy of an experience in a long time. I've got some cleaning to do.
Tore the engine down close to studs. No measurements yet, but everything looks to be in fantastic shape. Mains and big end bearings look new. Crank is in fantastic shape. Cam journals are in great condition. Cam is in good condition. Cam followers are in great condition. This is all very great news!