It should at least try to start on starter fluid if there is spark and compression. The gas may be bad, but not likely to be the critical problem if it wont start on the starter fluid.

You might jumper the fuel pumps to run continuously and then try starting it. This will be a good diagnostic test, but a safety hazard if a fuel leak occurs. Don't drive it this way.

Have you checked the rpm sensor? Maybe it got damaged during the head removal.

Dan