Bit of a problem
Had oil in water and no water in oil, change the inlet manifold, then took off the thermostat and water pump, flushed the engine by putting a garden hose in where the thermo goes and waited till the water coming out where the water pump was, was clean and free of oil. I got a compression tester off a mate this day as well so while the water pump was off i did a test, couldn't get the spark plug out of cylinder 5, so i tried 3, had to take the o-ring off the end of the screw plug because it wouldn't fit otherwise so i am unsure of the accuracy of the reading, but i pulled 5 1/2 bar (which i know is too low) after a couple of cranks, pressed the pressure relief valve and water came out, now im pretty sure this is a head gasket but as the water wasn't moving around and just sitting in the block, could i have screwed up the change of the inlet manifold as it was the first time ive done anything like this before?
Just wanting to know before i either have a go at the head or sell it or something

Thanks
Jake