Advice Needed - Can't Start Rebuilt 273

Is the car an automatic or manual trans? If it's a 4 speed find a hill or get a tow........ desperate times call for desperate actions!!!

Did you ever replace the plugs? I had a 69 340 Dart that I put a new set of Champions in. After about a 1000 miles it got real hard/impossible to start, long story very short we put the old plugs back in it and it fired right up.