I would recommend using a petroleum oil with plenty of break-in lube. The straight 30 WT Shell Rotella CI-rated oil is a good choice. Rotella does come in a 10W-30 WT if car will sit outside in the cold. Others fortified wi/ extra zinc-phosphates such as B-Penn are good too.
The Synthetic oils may take longer to break-in the engine. Rings need to be seated quickly. Assuming correct start-up procedures and NO idling for first 30 minutes of engine running; you get the engine basically tuned and drive it a bit aggressively; Do not baby the new engine. Changing to a synthetic after the second oil change 3-5K miles is fine.