I recently finished a 400 sb build that someone else started. The heads were machined and ready to go when I got it and the block had yet to be torn apart. I took it apart and inspected and all looked real good as if the engine had very few miles. It didn't even have any ring ridge. So I build it and put it in and fire it up.

First thing I notice is smoke from bank 2. Was blueish white. Second thing is the engine get warm Fast! And the coolant will not stay in radiator as if combustion is getting there. So I turn it off and go do something else as I scratch my head to figure out where I went wrong. Topped off the coolant after it cooled down and walked away again. Came back the next day and the coolant was very low again with no external leaks. Desided to try to start it and it would only turn an inch. So now I pull the spark plugs to see which cylinder is hydro locked. #4 poured water. Turned it over to pump it out and #6 had a little as well as #1 and 8. I think 1 and 8 might be because I forgot to put sealant on the intake and the coolant is getting into the intake ports (I hope). #4 And 6 is definitely a problem.

Heres the question. Before I take it apart, I will check all cylinders with my compression gauge. Is there a way to determine if the block is cracked or just the head gasket could be the problem BEFORE I take it apart? I will also check the head for warp-age.