So I got the head apart today. Few sticky old keepers were the main problem. Plus the first valve had a mushroomed tip causing some scoring of the valve guide on the way out. Good thing the head is getting new valve guides anyway.

Then the block came next. Wasn't bad. Had to rent a harmonic balancer puller but that was the biggest hurdle. I finally got to bust out my dial bore gauge and micrometers today and I found a few odd things when measuring the crank and bores.
Here are the measurements (from 1 in the front to 7 in the rear)
Crank Journal - 2.2994" 2.2994" 2.2996" 2.2994" 2.2995" 2.2997" 2.2996"
Main Bearings - 2.3010" 2.3010" 2.3010" ??????? 2.3020" 2.2999" 2.3010"
Clearances - 0.0016" 0.0016" 0.0014" ??????? 0.0025" 0.0002" 0.0014"
Add oddly enough, the crank was difficult to turn over after they were all torqued down... I wonder why...
So it looks like that plastigauge was right on the money as to how big my clearances are. I guess I should've plastigauged them all huh? Because these measurements would be redone at the shop, I was wasn't too worried that my bore gauge wasn't long enough to get the middle journal so I skipped that measurement since I only had a few hours left to finish everything up.
I'm not sure if that #6 bearing was just oversized or what but I checked the back of a few of the bearings and they were labeled STD so they should have been a standard size replacement unless that one oversized bearing was thrown in.
All of the measurements were done off of a 2.3000" calibration from the micrometer and that #6 bearing did indeed sweep past the zero'd 2.3000" mark into < 2.3000" territory.

Any idea what could've caused that extra small bearing?

All of those bearing clearances also seem a bit tight, I'm planning on having them polish the crankshaft while it's there. I understand the purpose isn't to take off material but will it happen to take off material in the process?

also... DO NOT EVER HAMMER YOUR HARMONIC BALANCER ONTO THE CRANK. I hammered it on during assembly (this engine never ran because of the main bearing clearances) and it totally ruined the thrust surface on the thrust bearing. Like it just as well could've been thrown into a dryer full of screwdrivers.

But anyway... I got the head all rolled up and ready to ship off. The stripped down block, old pistons, new pistons, and new rod bolts are in the truck. I gotta head back to St. Louis tomorrow but my dad is going to drop them off while he's in the city on monday. He should be able to drop off the head the same day or some time next week.

Some pics of the day's work

Had to get the original block out of the corner of the garage


Had to dig out the head from the parts. That's the 2nd junkyard block on the stand in the pictures


Clamped the head down and used a piece of angle iron with a slit cut in the end plus some cardboard shoved in the combustion chamber to push against the valve to compress the spring and get the valve out.


Removed the manifold studs


Lots of gross buildup on the intake valves.


Head all disassembled

69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.