To the OP. Make sure you check that block for any breaches of the oil return holes to the water jackets. My block had this and I did not discover it until just before initial fire up!! I had to take the motor out of the car. Tear the entire block down and clean it all out and re-assemble it after I fixed it.

Just look down the oil return holes with a flashlight and make sure there are no holes entering from the sides. It is easier to spot from the bottom of the block. Looking up from where the oil return holes enter the oil pan area.

I fixed the problem by putting a tight fitting sleeve inside the oil return hole with some metal epoxy. I had my machine shop at work make the sleeve for me. So far so good.