Best Stock BB Heads?

I agree with the sentiment of using whichever heads need the least amount of $$$ spent to make them servicable.

The “best” ootb stock std port I’ve tested was indeed a 906 “F” head.
However, not all “F” heads are great, and I’ve tested non-F heads that were better than some F heads.
They are after all just castings........ and they’re not all exactly the same.

For a novice who’s going to do a little clean up, imo the 346/902/452 heads are easier to do and have a higher chance of making real improvements to than the 906/915 heads.
For an experienced head porter who has the extra time it takes to make a 906/915 work....... they do have more potential.

That being said...... unless the cores you’re going to use need very little work....... you’ll be better off buy new aluminum heads....... from both a cost and performance standpoint.