How many times did you turn the engine over on each check? You should turn each cyl over 5 to 7 times and check ea cyl 3 times and average the readings for a true reading.

 

Thanks for all the help guys. I pulled the head and the gasket was blown between cylinders 5 and 6. It was a felpro from a previous owner.

One last question. What is the best way to clean the block surface area?