66 C10 sbc 400 compression issue.

[Captainfab]

I hate to say it, but it sounds like you have a cam lobe going flat.

Originally Posted by sweetlil66

Update.
Got the new head back on. Starts and runs great. Engine sounds good.
New issue.
Today when I cold started the truck the oil gauge showed 50psi. After running for 10mins the gauge fell almost to 0. *My after market - cheap gauge from orallys said 0 wasnt showing any oil pressure* If I gave it gas it would increase almost to 35/40

The one on the dash showed i had oil pressure. At first start up it went almost to the 60 mark and then after running 10 mins it moved down to the 1st mark (Between 0 and half)
If I gave it gas it would raise a lil past half way.

There is no knocking or such.

I thought I noticed a push rod tick on the side with the new head so I pulled the valve cover with it running to try and ajust it and noticed the very rear rocker doesnt apear to be moving as much as the others.