I replaced my motor with the sane motor just a year new my truck is a 99 silverado 1500 4.8 ls RWD An donor truck was a 2000 silverado 1500 4..8 Ls Rwd An I am Getting no spark I've changed racks I've changed Wires Plugs r brand new AN GAPPED correctly crank sensor is changed Someone Told ne I need two get the pcm From the donor Truck because they are programmed to the vin? BUT IF that is the case Is the pcm Programmmed to the vin of the truck or vin or motor? OVERALL QUESTON IS Couldn't not have the donor pcm Cause my no spark

 

I just helped my nephew change heads on a Vortec engine, all that was left was the short block, it, the engine block, was the only part not changed out. After assemble she started right up. The computer didn't need reprograming and why would it need to be reprogramed anyway, there's nothing to reprogram. If it was running before the swap, it should still run. Sounds like you got an electrical issue, if no spark. When I do swaps I use parts that I know work, because I they worked before I started the swap. Did the original swapped out engine run before the swap ?

 

the motor Had bad headgadket an Hydrolocked on me