stock fuel presure?

I have an '85 euro 911. What is the stock fuel presure supposed to be. It read 40 psi on the guage. Is this correct? Thanks.

[stlrj]

My Spec Book says 2.0 bar at idle and 2.5 +/- .2 bar (engine stopped, fuel pump bridged)

"1 atm = 760 torr = 14.7 psi. Bar (bar), The bar nearly identical to the ... Therefore, 101.325 kPa = 1 atm = 760 torr and 100 kPa = 1 bar = 750 torr. ..."

Joe

[cgarr]

Engine off with a relay jumper 36psi Engine running 29psi Engine running with vacuum hose removed from the pressure regulator 39psi Information on the board, priceless

Thanks to both for the info.
I am experiencing knocking at 4k rpm under full throttle. I'm going to check the plugs next. then give Steve Wong a call since I'm running one of his chips. Anything else I should check?