Cranks burn no start no fuel pressure

Test for key on power at the trunk mounted IFS switch. Use a KNOWN good ground. What to do next depends upon the test results.

Did you remember to re-install the ground strap from the left hand motor mount to the frame rail?

But after a motor swap I would double check the CCRM/PCM ground. There are larger black wires with a white stripe that goes around the battery to a larger round single pin connector.

Double check there's key on power in and out of fuse F2.34, F2,2, and F2.8

1999-2004 MY fuse panel schedule:
https://www.allfordmustangs.com/for...r-swap-wont-fire-please-help.html#post2669271

Here's some more information.

1996+ Crank with no start check list
https://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838