Hello, I'm Danny.
First thing you can do is perform a a "wet" compression test. Add a small amount of motor oil into the 90 lb cylinders and see if the compression readings come up. If they do that means the piston rings are worn. If you do that and they don't come up I would suspect a faulty head rebuild. Hope this helps and thanks for using 2CarPros.
Danny-
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Saturday, October 5th, 2019 AT 4:08 PM