I have an aluminum LS2 i'm building and putting in a LSA forged crank and good rods and pistons. Shooting for around 800whp with blower. Daily driven. everyday.
I have some calico coated clevite bearings and i'm trying to figure out clearances. I've heard .0012-.0020 is what I should shoot for on the mains. Is this accurate?

 

You're going to get different answers, but I would want to run about .002" if I were you. The coating is a nice feature and will let you run a little tighter, but it's better to run it too loose than too tight.

 

I've mixed and matched standard and extra thou clearance (except for the thrust bearing that has extra thou for both halves to get it closer)
ive resorted to using plastigauge as i'm stressing myself out checking every single atom of it with a dial bore and mics. Lol
But with a dial bore and mics, it seemed to be checking .0015 on the thrust bearing and around the .0013-.0018 for the rest (from memory. Perhaps not as big or small.)
With the plastigauge, They are all checking around .0015, maybe a couple tenths bigger or just a tad smaller (definitely not .001 More like .0013 or .0014).
I'm stressing myself out big time over this. Lol
i don't want it so loose as to not last many, many thousands of miles, but also don't want it so tight as to spin a bearing. I know aluminum helps open up a ton when warm, so i'm thinking this is good?
I know people will have all sorts of opinions.
I want to hear them all.

 

I'm not surprised you're getting tighter clearance on the thrust, Clevites are usually tighter in the thrust for some reason. If you have mixed shells in the other bores, personally, I would go ahead and put in all X bearings in the tighter bores. I'd be fine with .0018" with coated bearings, but .0013" is pushing it IMO. Especially with a blower.

 

See, they are all much closer to .0015....
the .0014 or possibly .0013 is an outlier.
I hear what you are saying, though.