I recommend that the engines be run in on 10W40
oil. If you are in a hot climate or it is summer I do not see a problem with the 20W50
oil. Most people do not drive these cars when it is real cold out but if the temperature was at or below about 40 degrees much I would stay with the 10W40 during this time. The only problem I have seen with the synthetics is that they seem to seep through some of the gaskets when regular
oil will not. I feel that the 2500 miles should be enough break in time for the engine. Thanks and good luck, Keith Craft