This morning I installed piston 5 and 6 and plastigauged the rod bearings to 0.003. Perfect results all around. Everything is smooth, the babbit on 6 was like new. I did not have to remove any shims, they were already the right plastigauge. Ready to do 3 and 4 tomorrow.
I spent 3 hours on my back a few days ago trying to get piston 6 in. No matter what I did, it wouldn't go in all the way. The 3 compression rings jiggled right in, in less than a minute, but the oil ring was hung up on something, because the piston at that point had no wiggle room. I could get the oil ring into the casting but not into the sleeve. I took the piston in and out half a dozen times trying to figure out the problem, maybe the bore was too small at the bottom and the rings went to zero gap and got stuck, maybe the oil rings weren't the right shape to taper into the cylinder sleeve. I thought of everything and experimented, and then after 3 hours I discovered, about a quarter of the way around the bore at the bottom, the cylinder sleeve was not tapered smoothly at the bottom, there was a small ledge of around 0.025 inch thickness where the sleeve stopped at the block casting, that the oil ring was getting stuck on. I could actually stick my thumbnail into it. I thought all week how to solve the problem. Maybe get some really thin feeler gauges around 0.08 to straddle the ledge like a shoehorn. Then I thought, it would be better to get some thick feeler gauges, shove them in around the ring and butt them into the ledge. That's what I did, I aligned the gap of the ring to the offending part of the sleeve, stuck two feeler gauges of around 0.030, one on either side of the gap, and shoehorned the oil ring on them, couple soft taps with the rubber hammer, and BINGO the piston went up and the feeler gauges fell down. I had to do a similar thing getting piston #5 in, but by then I had the knack.