So I did the lockouts on my 3v bullitt. Tuned out the VCT as well and have the cams set to a full advanced position. I heard I’ll lose performance, and MPG, but I’m getting 21.2mpg and she feels even more jumpy than before. But that’s not my question here, what’s the break in period of the new phasers? Had a shop tell me 3k miles but it seems weird that it’s a full oil change of driving less than 3k rpm. I’m doing it just in case but wanted to know anyone’s opinion.

 

As far as I know there's no "break in period" for the cam phasers but at the same time, I wouldn't go beating on the engine from day one.
Locking the phasers in full advance will only affect performance above 3750rpm, with a loss of ~8hp peak if you're still running the stock cams.