I havent pulled the rod caps yet. Just finished pulling the motor and trans out last night. The motor already had a forged rotating assembly. Should come in at a hair over 11:1 compression. Im keeping my AFR heads and roller valvetrain. It was a really nice street motor. Awesome power and torque all the way up to 6.5k
Its getting a nice big road racing oil pan and an oil cooler when I get it back together.

 

First post in a long time...

Having rebuilt engines litterally from parts begged, borrowed or stolen from junkyard motors, I can tell you that bearing clearance, or a couple of scratches on a bearing, will not result in high rpm oil pressure loss. At least not right away.

If you loose oil pressure as the rpms go up, that is classic rod bearing issue. Real easy to check for.

Remove oil pan.
Grab each connecting rod by the big end and shake it. If you can see it move - or feel any looseness at all, you have found your bad bearing.

If you are truely loosing oil pressure under load (not just under high rpm) - you have to look at the main caps. But that usually followed by the rod bearings going anyway. Also this isn't so much an issue on big blocks. More of 2 bolt small block main issue. Under heavy loads the main bearing caps 'pinch' in. Wiping oil off the crank. Not getting oil to the rods. 4-bolt mains help 4 bolt, splayed mains help the most. (and heavy duty caps). Circle track racers report seeing this at about 450hp level on a 2-bolt main block. But these guys beat on the engine for extended periods of time. Not a fair comparison for a street or drag race engine.

Bottom line. You have an oil pressure problem. You can a) replace all the bearings (rod and main) and add a new oil pump and drive for another year or 10 (yes big range). Or you can rebuilt the engine and know its put together right and drive another 200K miles. It sounds like you already have the engine out. I'd disassemble it and take it to a machine shop to have it inspected. Locally the guy will clean and mic out the whole thing for a couple hundred. Then you decide what machine work you want to do and what parts you want to replace. Personally I would only deal with racing machine shops. I've found some 'ring and bearing' shops that don't even know what a torque plate is.

BTW, get the book "How to Blueprint Your Engine" best discussion of machine shop technique and options.

 

Just BEND the DAMN thing and it will fit just fine.

 

Offended? Don't be. We're saying almost the same thing. I agree with you that a bore gauge is the way to go. But, absent that, plastigauge will at least tell if you are in the ballpark and it's better than just throwing it together.

 

I still stand behind what I said and that will never change. Plasitgauge it OK for rebuilding your stock L48, anything above a low power stock rebuild and you should be requiring accurate measurements, and I did say walk into high performance shop and ask them if they use plastigauge. I stand behind that too.

I did preface my response with "I do not want to step on anyone's toes" and I didn't want to. I don't make this stuff up and I am trying to help that's it. If I offended anyone I apologize, sometimes my posts come off a little to aggressive. but after 10 years here the post is meant to help and usually does by this method.

I could give a rat azz if anyone thinks I am smart or stupid, but in general I believe my posts have helped more that hindered. And this is the reason I have stayed here for 10 years, I don't want or need anyone saying MH your the greatest, I would rather see someone post and say thanks you insight helped me fix a problem. And 99.9% or my posts come from busted knuckles I have got when I answer a question