Where is the crank and cam censors located in a 2003 gmc safari

Did you check the plugs, wires, starter motor? Also verify and confirm there are no vacuum leaks?

Check the fuel pressure

Have you checked your cam sensor?

Replace the FUEL PUMP RELAY. Its located in the under hood relay center. This relay primes the pump with the key on, about 2 seconds, then the pump will not run until the engine has oil pressure, then the fuel pump is energized.

how much fuel pressure you have when turn key on

next would be the crank sensor

Check the starter relay.

It might not have enough fuel pressure. Try spraying carb cleaner into the throttle body when you crank it to see if it fires.

check that and spark first.

Since you replaced the distributor, are you sure it's properly timed? Hook up timing light and try to crank. It should show you where your timing mark is. It will also verify that you are getting spark.
You need to start a systematic check. Is it electrical, mechanical, fuel related? Need to do more checking and maybe we can get that puppy going.

Good Luck