Re: [MBZ] When to use Mobil 1 after engine rebuild

[Peter Frederick]

No more than 500 miles.  Make sure you do some full throttle high load 
runs (steep hills in high gear) first -- this polishes the cylinders a 
bit and "seats" the rings.  If you don't, oil consumption may stay high 
for a long time, MB cylinder walls are fairly hard, and they don't use 
scraper rings.

Change the filter at the same time.
Peter