Too much oil pressure

[4x4 power]

I have just completed my first 6.5 engine rebuild. I started it last night a I have a lot of oil pressure, the gauge was pegged at 80psi. I am going to install a mechanical gauge to verify the finding. Can I switch to a 5W30 to help lower pressure, should I be concerned, what do I do? Thanks Joe

[whatnot]

If you have the wire to the sender unplugged, it will peg the gauge to the top.
Is it at zero with the engine off and the key on?