Tires on the ground and in gear?
The last thing you did, take back off.
HPFP cam follower stuck in bore not allowing rotation of cam.
Cam follower installed dry?
Assembly of new internals for HPFP correct?
HPFP spring retainers misaligned with spring keeper? Double checked with a tap of spring and plastic hammer to double check fitting of retainers into valley of spring retainer?
Simple projects, some times just undo what you did.
When you discovered rotation failure, reverse rotation also fail?
Please don't use starter or more force. Think of previous steps and walk it through.
HPFP Cam lobes move HPFP follower, that action moves pump shaft that compresses spring you installed with piston cup. Any of those wrong and you have a locked up intake cam.