Sounds like you may have the incorect fitting or your just having a bad day.

I personally do not like to mount any hardware directly to the block as I have seen issues in the past with fittings cracking.

What I have done is used a 6-8 inch 3 an line from the block and mounted a T on the firewall instead of directly on the motor.

My personal preference is to use a sandwitch plate for oil supply.