It's not GM, but...
It's a build-it-yourself fuel-only engine controller.
I believe it was developed by a couple gents from the DIY-EFI mailing
The URL for info is:
Anyone messed with one of these? I was thinking about building one just
for amusement, probably to run with a GM TBI; it appears to be a
two-injector-driver L/R batch fire system.
It's a speed density system, so coming up with the initial program could
be fun, but hey, if I wanted my junk to actually run consistently, I
wouldn't tear it apart all the time.