Well I have an Ls1 in a 2000 Trans-Am. 185k miles on it. Standard bottom end, with Patriot heads/cam package along with many other bolt ons. The bottom end has done well to last this long.
On start up good oil pressure 40-50psi on idle. Once warm this bounces between 0 and 80psi, like pulses around every revolution on the engine. Some low end noises, which a mechanic had a listen and thinks it would be the main bearings. This seems to explain the noise and the oil pressure.

So it's gonna be engine out to strip and inspect. I have never done this before. I'm comfortable taking heads off as done that a couple of times when installing the heads and having to change the liftes a couple of years ago.

I guess I will have a few options and some unknowns until I take it apart. I quite like the sound of 383ci.

So I guess my options are.
1. Buy a complete built 383ci short block. $5k ish
2. Buy a stroker kit with bearings. $2.1k. Will this need balancing?
3. Find out what has really failed and replace appropriate bearings <$400 for cam/crank bearings. This is the cheapest way, but still everything is still standard, could last another 100k+ miles.

I'll change the oil pump anyway when I take it apart, and as its in bits, I could put in a cam with larger bumps. Currently 226/226 and fails emissions, so going bigger won't make any difference.

So this is the start of my journey. Wanting to get it back on the road for end of March. Two things against me. Funds, or lack of, and I'm in the UK. These two I can work on, and not concerned about ordering direct from the States. Brought the TA from the states when it was 2 years old.

However my lack of experience could go against me, but this forum is brilliant for finding answers. I'm sure what I'm doing, someone else has gone through.

Currently building a shed in the yard so I can take the engine out and work on it with some light and shelter.

 

Sounds fun!

​​​​​​Just a thought....is it possible that your Oil Pressure sending unit is malfunctioning?

 

Yes quite possible. I brought a new hand held gauge sensor with 13 different attachments. After taking the intake manifold off, found that not one of these attachments would fit. It would have been nice to confirm.
It is odd that the oil pressure seems okay when cold though.
Drove it to work today, its only 1.2miles, missed all the traffic. Temperature got to 1/4, no issues at all, no funky noises.
Over the weekend we took it to full operating temperature on the driveway, and inside the car you could hear a deep banging sound, yet at the front of the engine it sounded okay. The mechanic that was listening seemed to think its the main bearings loosing pressure, which could explain why it only does it once warm.
I've got to drive it back home yet, so will be listening for noises. I have a dash cam, so it may pick up any funky sounds. Its soo hard to describe a sound.

 

If you have a bearing issue, there is a strong possibility that your Oil filter will show evidence. Perhaps cut it open and have a look?