Thanks Mike. My builder last time around did .0027 on the rods, .0025 on the mains. If the main journal diameter is 2.75" the rule of thumb says .00275" I'll have another conversation with him, but in the end he has 30+ more years of experience building Hi perf engines than I do, so I'll let him make the final decision. I will however go with a lower vis oil in the future.

I would not run 20-50 with that for mains, I tried once many years ago... it didn't last, did nothing different besides snore clearance and never had an issue again.

How many engines you build in the last ten years? Don't take it wrong but it looks to me you have nothing but problems and I see it hard for you to give your opinion or advice on building engines.
These clearances work fine it's what I run to .0001 with hot oil befor I punish them. Never had bearing issues because of clearance.

12+ years on efi whipplecharged engines w/ .0027" mains and 15-50 mobil1 syn.and the running joke is,,I rarely change my oil,,still beat the schit out of them.

I posted up a massive 502 MPI gen-6 oil thread years ago I think the point of what everyone's missing that still holds true is a stock gen-6 502 has tiny oil lines with tiny inside diameter on the fittings as small as three eighths of an inch
That works fine with a stock low volume oil pump and tight rod and main bearing clearances but as soon as you put on a high-volume oil pump and open up the main and Rod clearances the oil lines become a restriction. Now the block oil bypass valve opens up all the time circulating hot, unfiltered oil throughout the motor and it also opens the bypass valve in the pump as the oil can't go anywhere so in the end you're making 70 PSI oil pressure but only seeing 40 at the motor after it goes through all the lines. I personally saw this on my gen 6 502 mpi years ago, oil was hot and after hard runs dipped to less than 10 psi at idle. I upgraded everything without pulling the motor before i hurt it and it lived a happy life.

I learned about the gen6 weakness wen I put an aluminum headed 502(basically a boat engine set up) in my 93 gmc truck.I had the oil pressure sensor in the oil passage off the #1 main,,it was scary how low that oil got before I made/solved all the oil passage/supply short comings.
engine still alive to day,,roaming the roads and logging roads of NH.

articfriends summed up the mods beautifully.

http://www.offshoreonly.com/forums/g...-hardware.html

So no one thinks Redline 5W-30 would have kept this from happening.

maybe borgie,lol.

Articfriends: Actually your post about oil lines is what prompted me to upgrade everything from stock stuff this past summer. Unfortunately for me the damage was apparently already done and the eng's started to seriously lose oil pressure a couple of months later. However: here's my question- in my case I upgraded the oil cooler in 2013 so oil temp was not a problem except for the first few runs when the eng was new (220 most of the time, 260 max WOT measured before the filter or cooler). Also, with only 90 hrs on them and 25 hr oil changes using synthetic 20w-50, it doesn't make sense to me that some of the oil being recirculated was non-filtered would be enough to cause the bearing breakdown. In fact my builder says that the bearing wear is indicative of oil starvation, so do you think it makes sense that the combination of oil passing through the narrow 3/8 lines plus what was passing through the bypass was still not enough volume? Believe me I'm not trying to be hard-headed I'm just trying to make sure I know what the real problem was so it doesn't repeat.