Broken Bolt

Hello all im currently replacing the timing chain on my 72 dodge dart swinger with a 318 after a failure at 45MPH. i took everything down to the water pump with no problems then i broke a bolt..:banghead: the upper left hand bolt (as seen in attached image) from what i was told its a water jacket bolt into the block today when i finaly got the crank bolt and harmonic off and oil pan bolts off the timing chain cover and tore off the gaskets as best as posible the timing chain cover STILL wont come off a guy told my dad its a common bolt to break and it goes into the block so i have no clue why the cover wont come off i already broke the cover using a flat head to pry off the right side but the left side just refuses to come off im open to any way to get this darn cover off! all responses are thanked :)
You might have some engine damage, if the chain failed at 45MPH the valves may have kissed some pistons. I'd look for some bent push rods too, time to open up the valve covers and check them out.