1st gen car has been stored. Has high pressure oil regulator. Has factory oil pressure guage in dash plus a oil pressure guage with a warning light plumbed in. Motor had great pressure when put in storage. Recently when I went to start, all guages were not registering any pressure. Oil dip stick shows full.

If it wasn't for two different oil pressure measuring points (stock location and the added block oil filterfor mounting aftermarket guage and light) I would assume the guage or sending unit was faulty.

First guess is oil pump has failed. Any other ideas? Is it common for the oil pump just to stop working when motor isn't run frequently? How can I confirm the diagnosis without getting to the oil pump?