help 96 monte will not start

help i got a 96 monte that will not start i replaced the dome gasket and replaced every thing. ran fine when i started the work on it. have noticed it is getting gas and spark but just will not start..help 3 days at it now

an up date we are not sure but think the timing chain may have jumped its timing with all off the water that was in the oil any one got any idea's...