Was driving on the highway and heard a loud pop it sounded like my muffler blew up. Now when I crank the car it won't start and it makes a weird almost cough and grind sounds. Any ideas what it might be? I changed out the water pump, head gasket, intake and exhaust gaskets, new starter, new distributor, I even changed the intake manifold and it still won't budge I also lost pressure in the gas pedal.

 

What kind of car is this?
Year, make, model, engine, etc...