HP EFI seems to be the more basic version of Holley's Dominator ECU. It shares similar harness connectors and has similar functions, but is more limited in terms of inputs and outputs.
This forum thread contains a lot of pretty good information about how to make the Holley HP EFI and Dominator run on a 3800:
https://forums.holley.com/showthread.php?16249-HP-EFI-On-3800-V6-Engine/page4
One of the biggest issues in getting started that was noted there was how to send the ECU a crank signal.
The solution presented on that page was as follows:
So in review, the GM Series II & Series III 3800 engines will run just fine on the Holley system, with LS coils and using the factory crank & cam sensors. You will need to set the Firing Order to 5,4,3,2,1,6 Use the Custom Ignition Type: Crank - 1 Pulse/Fire - Digital Rising Ignition Reference Angle 75° and using the 3x reluctor on balancer. Cam - Single Pulse - Digital Falling Inductive Delay - 100
A later post on that page mentioned it would also be a good idea to synchronize timing in Holley as well.
https://forums.holley.com/showthread.php?2577-Synchronizing-Ignition-Timing-Holley-EFI