3406E Break in question

Thats fine on a synthetic so long as it doesnt leak.

For the break-in, oil is oil as long as it meets spec for the engine, drive it like you stole it for a month, if the builder did a good job, that should do the trick, if they did a crappy job, they will have to eat the repair bill now as opposed to fighting it 300k later

 

Most advise to break in with conventional, then switch to synthetic.

I often go against conventional (pun intended) wisdom, and always have here too.

I always advised customers to break in with the oil you're going to run.

My 60 has 256k running on Mobil full synthetic. Oil usage stopped around 36k IIRC.

I do change first oil @ 1k, 2nd @ 5k, then every 10k till oil usage stops.

 

You failed to say what weight oil your running.

Lower weight premium oils have shown me no MPG increases, however they have showed me lower oil pressures.

Currently running Mobil One Extreme 15w-40 in a DD13 with 500K miles.

I'm a big Jake Brake user and I wanna see that oil at 70PSI when I'm in 9th at 45mph and those cams are getting a workout downhill in the hills of WV.

(Edit to add) Nobody has Jakes like a Detroit....

 

When that 3rd stage Jake kicks on, whoa...better not be on ice.