V8 3.5 oil pressure

[RED1001]

I have new smiths instruments in,i recently fitted a new voltage reg to correct the temp gauge, that worked great but now the oil pressure shows nil, does the oil pressure gauge require connecting up to the reg? The gauges start with 'B' so the reg is correct.

[Clive]

If it is an electric gauge, then I think it would, although I don't see why it is currently reading zero.
If the voltage is not regulated the gauge should still read, but not accurately. If it isn't reading at all, firstly check there is power to the gauge, then follow the wires to the sender where it earths through. Disconnect the wire to the sender and touch it to the engine block and see how the gauge reacts.
One voltage regulator should be sufficient for up to three gauges.