1995 Nissan Maxima replaced heads and it wont start

COULD REALLY USE SOME HELP PLEASE recently had camshaft explode inside of the head and then replaced the heads with remanufactured ones... One of the casting #s was not a exact match but all of the ports and holes and threaded holes matched up and it went to a 38u motor so I took them replaced all the applicable gaskets and hoses and the maf sensor and cam position sensor and the crank position and reference sensor verified that the injectors are clicking and fuel rail has pressure and that coils are firing spark and engine is in mechanical time and that compression is in the correct firing order sequence and changed the ignition circuit condensor and the alternator starter battery checked the computer with its self diagnostic mode and it tested fine but the #$%@ thing still refuses to start SOMEBODY FOR THE LOVE OF GOD HELP B-4 I LIGHT THE CAR ON FIRE. I AM NOW $3,780 DOLLARS INTO TRYING TO SAVE THIS CAR.