For the first time ever (yeah, I know...) I decided to check the crank end play on my engine as I reassembled it. Zero.

-Apply deadblow hammer judiciously to the snout and flange of the crank to "set the thrust" on #3. Zero.

-Loosen #3 to finger tight on the studs. .005".

-Repeat hammer, tighten studs to 45, repeat hammer, tighten to 100, repeat hammer. Zero.

-Re-loosen studs to finger tight. .005".

-Consult 2 engine builders to confirm my suspicions. One said "Don't worry, if the crank turned by hand before the pistons were on, it's fine... I never bother." The other said use emery and sand the bearing face, but after I informed him of the difficulty removing the bearing shell, he said "Check the cap thickness", confirming my suspicions.

Remove #3 cap and inspect. As I remembered, the bearing shell is VERY difficult to remove. Hypothesis - bearing cap is too thick and flaring the thrust faces. Test - measured the grooved area around the bearing saddle and found that the bottom/center of the groove is .0035" thicker than by the ends. I then measured the overall thickness of the caps and found it to be even within .0005". I used a .015 travel KURT indicator and found that when laying on the mill table, the thickness of the cap was even, and the side of the thrust groove was parallel to the caps outer face, as it should be, but the other side , the grove was off by .003, with the deepest part of the bearing saddle being the thickest point.

Solution: I took a fly-cutter and milled down the groove until the thickness was even. As I progressively cut deeper, the edge of the area that was being cut moved closer to the cap mating face. At .003 there was only about 1/8" that hadn't been touched by the cutter., . I remeasured the cap and the out of parallel was below .0005". I r-einstalled the cap, tapping fore and aft as I tightened it down then re-measured the end play. .004". Notice the clearance increased more than the depth of cut. The overly thick main web of the cap had been flaring the sides of the bearing out.

Lessons learned:
-Always check the end play
-Never assume aftermarket parts fit regardless of the quality and/or brand reputation.
-Don't listen to the one guy who says "No problem, it'll wear in."
-Don't fix the symptom, find the problem and fix that.
-Even though it ran fine before with the same parts doesn't mean it was right then