The plot thickens.
It seems the fuel pump is not putting out consistent pressure. Several measurements taken with the fuel filter out of the loop showed readings ranging from 2.5 to 3.25 psi. After each reading the pump was shut down and pressure allowed to bleed down to zero. I think that is a lot of variation, too much.
I am ordering a new holley pump, this one
http://store.summitracing.com/partdetail.asp?part=876&view=1024
I will pair it with the regulator I already bought.
I cut open the fuel filter. Didn't find anything alarming. I don't think that was the problem, but obviously it is getting replaced. The good news is I probably don't have to pull the tank.