Ray, in line with the oil filter on the left side of the engine heading forward, there are 3 plugs that tap into the oil gallery. Any one of these can be used for an oil pressure guage, but probably the middle one would be the best, as the next one back is close to the engine mount.
The pic below is where a tee has been put in to run oil to the rocker gear on my 56 engine, but the 1960 292 i have spare is not tapped in this position.
you could do similar and put the guage adapter in place of the copper tube,
but i would just screw the adapter into another plug hole.
South Australia