Seen it, forgot it....
 

I got questioned on engine break-in period. How long for engine break-in, and how long before running synthetic. I know ive seen a post/thread on all this, but I cant find it.

...break-in period for any new vehicle is specified in the owner's manual. In the bad old days (of imprecise tolerances and ordinary materials), break-ins were painstaking and tedious. Now, they amount to driving at a few different speeds and loads, and avoiding some more severe conditions for the first five hundred miles or so. I don't recall exactly what it was for the Mazda (though I did follow it). That was 32,000 miles ago! Consult the manual.

Basically the question was, "when can I run synthetic in my new motor?"

I believe it's only like 500 miles..newer engines designs require MUCH lower break in periods