Glad some answers are there and things can be fixed and that the rotating assembly is pretty much OK.
What is your evidence that lower end oil flow was low? Since rod side clearance is usually much larger ( 0.010" for instance) than the bearing clearance ( maybe 0.0025") the side clearance has no impact on oil flow/pressure as I understand. Slightly increasing the bearing clearances my help your flow. I know there are differences of opinion about bearing clearance depending on use, rpm's, power level etc, etc. As long as oiling system can keep up with it and considering how much you are leaning on this thing (10k rpms and who knows how much power) a somewhat larger than average clearance may be helpful.
A comment from Darin Morgan of Reher Morrison racing engines:
If your having bearing problems with 05-30W synthetic oils your problems are not with the oil as much as they are the clearances and the machine work. Bearing misalignment or worse yet, to tight a clearance will hurt you every time. A good line honed main and properly trued and honed rod housing bores seem like a given but they seldom are. They need to be addressed, checked out and honed by a professional that knows what he is doing. You need to have .003 on the rods and .0035 on the mains or your playing with fire. We run .003+ on the rods at all times never less than that, ever. We run .0035 to .00375 on the mains and never less than that, ever. On engines with higher loads the clearances go up never down. Pin bores can have up to .00225 for clearance on some engines with high vacuum in the crank case and good oil control in the pan. The better the oil control and vacuum in the pan, the less oil the wrist pins get! We run 0055 (not a misprint) weight and it about the thickness of water. we run .0035 on the rods and upwards to.004 on the mains in the PS engines and the mains last all year long. Our 1300 horsepower Super Series engines have .003 rods and .0035 mains and run for 600 runs down the track! The record so far is 675 runs by Scotty Richardson.
(1) Get a good, professional machinist to line hone the mains and hone the rods properly.
(2) Make sure you have proper oiling. If your pressure fluctuates during the run,, you have problems.
(3) .003 rods and .0035 mains for clearance
(4) Use a good synthetic 05-30w oil like Mobil-1 or Castrol syntec
(5) In my personal opinion you need to stop using any oil from Amsoil. That is not a racing oil even if they say it is.
And one from Larry Meaux, also I think one of the smartest guys around (Pipemax fame)
"
Darin, all i can say is "I'm glad you Posted this first"
like your results , for the last 20+ years i've run nothing but
.0035" to .004" rod and main bearing clearances
on every Engine i've built, even my old Chevy Suburban Dragster Trailer Tow vehicle's SBC 406 cid has .0035"
never had 1 rod/main bearing failure yet in 20 years, not one !
Bearings look new -to- almost brand new after full season or more,
and most of time i never replace the main bearings, just new Rod Bearings instead on rebuilds.
all the Engine Builders i deal with run .003 to .004" Rod/Main clearances,
and most just tell Customers they have .002" to .0025"