need help with a 1999 gmc 7500 with a 454 with the coils on top of the valve covers a guy in our shop swaped the engine out now we cant get it to run we have change the cam and crank sensor but it still has no crank reference we changed the pcm out still nothing now we are at the point where we will take any advice we did order a reluter ring for it but any info would be most helpful thanks in advance