adding second mechanical oil pressure gauge
 

the 39 flathead has the original oil pressure gauge setup and would like to add a backup mechanical gauge. I don't trust the old gauge and don't want to disconnect it. Can I install a tee setup and so both gauges would function? Thanks

Re: adding second mechanical oil pressure gauge
 

The short answer, yep. Is the current sending unit at the driverside rear of the block? There may well be an unused opening that has a plug in it there.

Re: adding second mechanical oil pressure gauge
 

The two stock openings are very close together but at 90 degrees to each other. If you don't have an oil filter one, the one pointing left, will have a plug in it...you need a 1/4 to 1/8 pipe adapter, probably already in the gauge kit, and the fittings that come with the tube. And a bit of manual dexterity...
If you have a filter, Tee into the line from back of engine BEFORE the last fitting at filter. This can probably be done with just the right female in/male out Tee fitting and a little pressure on the line to add a bit of curvature to make space for the Tee.

Re: adding second mechanical oil pressure gauge
 

Here is my arrangement on the 39 P/U, the first pick is an actual gauge with a ball valve that I can observe while out of the cab.

The second picture is the sending unit installed were the original one would be for a newer oil psi gauge in the cab next to fuel, H2O temp and volts.

Re: adding second mechanical oil pressure gauge
 

Just as a side note, the original Ford (King Seelley) gauges are very dependable and seldom if ever fail. The only "bad" ones I have seen where the ones that had been zapped by 12 volt conversions. Those are easy to tell because they don't work at all.
Just my opinion

Re: adding second mechanical oil pressure gauge
 

added oil sensor giving much better reading and bingo sprung a like and installing new line. Issue, came with very kinky coiled plastic line installation kit. Anyone know how to straighten out the line??

Re: adding second mechanical oil pressure gauge
 

My tee off for oil pressure mechanical gauge and maintaining original electric gauge. Vertical line is for the full flow oil filter system return