tried everything and cant get it started

I own a 1992 buick century and just moved to arizona from Oklahoma. On my way here the car overheated and stopped running. I have now replaced the head gaskets and manifold gaskets, cleaned the heads, put new plugs and plug wires in and now it will not fire. I can turn the key and it turns over fine but it will not fire. I checked the fuel pump and it turns on. I also checked to make sure the plugs were fireing and that seems fine I have rechecked all the wiring and I am almost certain it is all hooked up the right way. I am completely at a loss. Any help would be appreciated. Thank You

Since you have spark, you need to check the injectors and make sure that they are getting fuel to the injector and then the cylinder. If they are then recheck your firing order and all harness plug connectors. If the injectors are not getting voltage then cover the basics like fuses and pigtails. If the injectors are not getting fuel then check the fuel filter and the fuel line connections. Good Luck.