Use Molyslip E oil supplement in your oil.
Molyslip Canada Inc. :: Molybdenum Lubricants, Performance Lubricants, Copaslip Anti-Seize, EP2 Grease, Wear Reducing Lubricants, Oil Additive
This stuff contains both zinc and Moly. This is what I use for new/rebuilt engine run in.
then after the run in and on each oil change I add 1/2 a can the new oil change.
Thats plenty oil additive boost and cost effective.
You can buy this in Niagara Falls. CTC or Home Hardware.
The GM EOS oil additive is great stuff too. (Any GM dealer parts counter)
Home Hardware - molyslip
Do not use synthetic oil for the break in.
I've never been too keen on Lucas additives. I never use any other additves except the Moly Slip and GM EOS in my oil.
By the way synthetic oil is not any better at anti scuff than a dino oil.
The anti scuff is provided by the Zinc phosphorous additve and the Moly disulfide additves that are added to both dino oil and synthetic.
The advantage of synthetic oil is primarily temp/viscocity control and lubricity and service life extension , not anti scuff.
A pure synthetic motor oil has been found to cause issues with fat tappet cam/lifter rotation. (Because it is too slippery)
I would not run a 100% synthetic in that motor. And surely not for the break in.
I do not drain out the oil after the initial run in. Leave it in and let it and the GM EOS and Moly Slip additives do their stuff for 1000 miles.
It makes no sense to drain the oil right away. Just change the oil filter.
Takes more than 1/2 an hour to fully break in a motor. You are just dumping your money down the drain.