Volvo: New Engine, mineral oil, synthetic oil

Question

I got my cars(95 850 non turbo) engine replaced by the dealer.I realized they filled the new engine with full synthetic oil 5-30(castrol) now I'm confused because I knew that when the engine is replaced or overhauled the oil that must be used should be mineral oil. and after the break in synthetic could be used.. am I wrong? and are there any hints you can give me during the break in period?

thanks

Answer
Mete,
As far as I have heard new or rebuilt engines just use regular or synthetic oil, not mineral oil. I think that is old school engines of the late 60's 70's. Break in period on todays engines is almost non existent. I would just drive say under 75 mph and very the speed for the first 1000 miles.