In the process of a very slow rebuild and for some reason I'm thinking that all I need is one quart of break-in oil and the other quarts conventional of the same wieght.

Is this koesher? Or do I need to get six? Or just do six or so of regular and add a bottle "concentrated" break-in additive?

 

You need to use royal purple break in all 6 qts. Run it the suggested time then swap in your favorite brand of oil.

 

Sounds good, but what about a different brand? This a budget rebuild...

 

Lucas makes one. All the break in oils are expensive. I think they do make some sort of additive that has all the zinc and stuff you really need for proper break in.

Ive always just used castrol, and I'm not nice to my motors and they run strong.

 

I use Rotella T and skip the overpriced "break in" oils. They generally aren't necessary anyway, but I do like the additional ZDDP...which the Rotella has.

The "break in oil" thing goes back decades when manufacturers used a low-detergent, low additive oil to slightly increase ring wear to help them seat against the cylinder walls.
It hasn't been necessary for a long, long time...and no new car that I'm aware of rolls out of the factory with it anymore. Any good quality motor oil is just fine. If you are worried about the zinc/phos content- use the Rotella (or Delo or Delvac)- but even that isn't really necessary with the low spring pressures in the 4.0

 

But it is necessary with the flat tappet design of our lifters. I recommend Brad Penn, they have break in oil and regular oil that both contain the necessary zinc content.

http://www.penngrade1.com/Products/H...ak-In-Oil.aspx