The wiring for your oil pressure switch, is it one wire? Key on, is there voltage on that wire, there should be. If not, problem with wiring circuit or gage/instrument cluster. Youi can take wire loose from sending unit, key on, ground the wire to engine metal, the gage should go to moving. I don't like to peg out an analog gage. You could use an analog gage in place of the sending unit, to double check oil pressure. In the old days they used to say 10 psi minimum for every 1k rpms. I don't have your exact oil pressure spec?
As far as your fuel gage, you could use resistors between the proper wires, key on, at the sending unit. One resistor represents a full tank, the other resistor represents empty tank. If the gage reacts properly, the problem is the sending unit in gas tank. If it doesn't act properly, may be a problem with wiring circuit or gage/instrument cluster.