I don't think the euro motor has a different bore and stroke.
Check out this thread and ask CTaylor738 about his euro 3.8 liter engine he built for his 380 SL:
Wayward Woman Runs Better, Still Fails Emissions
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".