high oil pressure readings

I've just finished putting in pressure gauge on the filter outlet and found
high readings like someone had talked about in audi/vw forum. Can anyone
give me any help on why this would be high readings?
They also  stated putting it on the end of head where there is also another
oil psi termial couple, Does anybody know size of fittings needed? mm or
pipe thread? What readings do you get there? Hot ____ Cold___

Thanks Roger
PS this is on an 78 scirocco with 1.6