I hate to tell you this but it sounds like you could have a blockage it the block which means complete disassemble the engine and have the block cleaned. Time for a rebuild.

 

what would cause the engine coolant passages to get blocked all of a sudden or the engine to crack what tests could i do to deterine if this is the problem

 

Rust particles and other crap could be blocking the passages, so a pressure test is the first thing. If no pressure, and you are damn sure the gaskets were put on correctly, then take the radiator out and have it checked for blockage. If it is clear, and you know for sure that your water pump is working properly, then you may need to try an acid flush to unstop any crap that is blocking any passages. If that fails, then you may need to have the engine torn down and cleaned. Try the cheap things first. Test that water pump.