break in oil and changes

I also have a 408 getting ready for break in, I was planning on using Joe Gibbs BR 40 which is a 10w 40, I have a flat tappet cam and Im told this stuff has a very high Zinc content needed for break in, I wont run it more than 300 miles with it.Then I will run a high Zinc content 10w40 maybe Lucas, this was my engine builders recommendation.