L67 swap no crank
 

I did the l67 swap. Got the motor/tans and pcm out of a donor car. Donor car was a 04 impala ss. My car is a 03 monte ss. I got it ready to fire uo and turn the key and nothing. The dash goes off and nothing happens no click. I tried another pcm out of another sc car and same thing. Car ran fine before swap. I traded my factory pcm to junkyard for core. A buddy thinks the pcm has to b programmmed to the vin number. I have bypassed the ims in the trans. Have done the cats relearn multiple times with no luck. Motor does crank if i put power to the ppl wire on starter. What am i missing. Do i need to go get the bcm out od the donor car or have a custom pcm burned with ny vin??

You need to your PCM tuned to your VIN, your buddy is correct. The BCM and the PCM need to talk together, and that's not happening. I wouldn't swap your BCM, there are electronics and features that might have differed, and you could lock your radio too.