It all boils down to personal preference.
When I go to do a freshly rebuilt engine break-in run, I will spend the extra money and purchase an appropriate amount of SAE 30 Engine Break-In oil similar to
THIS PRODUCT.
The
Shop Manual guidance says to run the break-in oil for the first 500 miles, then change out with fresh oil that matches the current temperature and expected running conditions expected for your truck.
You can certainly run a multi-viscosity oil, but would recommend you don't do that until after the initial break-in period.
Others will chime in here with more info and personal preferences, but this is just my $.02 worth on the subject.
Dan
