Just rebuilt my motor and got it started on the stand. It got new piston rings and a few other things. Everything else was cleaned and machined. Should I be adding an additive to the oil for break in?

Also, oil pressure gauge is reading 70 off the filter housing. Is this good? Too much?? Thanks

 

Yes, a zinc additive is what you want. Follow your cam supplier for break in as well if new, typically don't want any idling for 15 min or so. 70 psi is fine, it will probably pull down a bit once warmed up.

I just finished a rebuild and first start was over 100 psi at 1500rpm. Dropped to about 35 at idle once up to temperature after 20 minutes or so. Still pulls up over 70 at rpms when hot.