318 - High Oil Pressure

My 2 direct experiences with too high oil pressure (very similar numbers to yours) is in:

1. blowing out the base gasket on the oil filter; the guy driving did not notice the smell and ) reading on the pressure gauge and toasted the main bearings big time (MY engine of course...)
2. overpumping oil to the head and leaving the pan dry and seizing a crank... BUT that was not a SBM with its oil flow restrictions to the head, so that is not likely going to be an issue for you.

If you are not racing this thing at constant high RPM's, then I'd correct it just because of #1 above. I'll guess that the pressure relief piston in the original pump is inverted or stuck. Easy to rectify, but a new pump is cheap. And BTW, just so you will know, a high volume SBM pump won't put any higher pressure into the engine, but will maintain better oil pressure at low RPM's.

I would not suspect oil out of the dipstick tube from this. MAYBE high residual oil levels could build up more oil under the valve covers. But your 2 last symptoms sound like either having no PCV valve in the engine, or excessive ring blowby (poor piston ring seal).