Maybe I can make some sense of the early first oil change.
Engines aren't broke in when they are built. Its after the installation.
When an engine is built, all the moving parts to include the bearings, piston rings, rods, crank, cams, oil pump, valves, etc.; along with the seals that hold the oil on its side of the engine, are lubed with an assembly lube for first start up. During the first 500-1000 miles, metal is worn from the rings, cylinder walls, crank, cams and bearing surfaces. This is break in. This initial wear continues up to about 3k miles.
As the particulates make their way to the oil pan in circulation, some of it settles to the base of the pan, some gets trapped by the oil filter. Usually by the time you hit the 3k mark, all the particulates have been trapped in the filter. (Hint)
Years ago, when and engine was rebuilt and installed, it was taken on a break in run which usually took about 30 minutes to run the cycles then you drove it normal for a thousand then changed the oil and filter. But, with better filtration and oils compared to 20+ years ago, you can stretch that out. You still have a break in and its a good idea to change the oil and filter early for the first one.
Now, as far as conventional over synthetic. Conventional creates more carbon inside the engine and breaks down quick. Synthetic is less carbon and last more than twice as long with better lubrication which helps with fuel economy and power.
Engines aren't broke in when they are built. Its after the installation.
When an engine is built, all the moving parts to include the bearings, piston rings, rods, crank, cams, oil pump, valves, etc.; along with the seals that hold the oil on its side of the engine, are lubed with an assembly lube for first start up. During the first 500-1000 miles, metal is worn from the rings, cylinder walls, crank, cams and bearing surfaces. This is break in. This initial wear continues up to about 3k miles.
As the particulates make their way to the oil pan in circulation, some of it settles to the base of the pan, some gets trapped by the oil filter. Usually by the time you hit the 3k mark, all the particulates have been trapped in the filter. (Hint)
Years ago, when and engine was rebuilt and installed, it was taken on a break in run which usually took about 30 minutes to run the cycles then you drove it normal for a thousand then changed the oil and filter. But, with better filtration and oils compared to 20+ years ago, you can stretch that out. You still have a break in and its a good idea to change the oil and filter early for the first one.
Now, as far as conventional over synthetic. Conventional creates more carbon inside the engine and breaks down quick. Synthetic is less carbon and last more than twice as long with better lubrication which helps with fuel economy and power.