Tallest Domino Speed Pyramid (World Record)

The tallest free standing domino speed pyramids EVER!
These unofficial record(s) were set using dominoes from http://BulkDominoes.com
Past Pyramid Records/Attempts:

Free Standing:
dominofan238 - 28 Stories
   • Former inofficial world record: Tallest sp...  
xDominoTeam - 27 Stories
   • WORLD DOMINO RECORD - BIGGEST SPEEDWALL  

Not Free Standing (supported by a wall):
StarRider - 37 Stories
   • World´s BIGGEST Speed Pyramid EVER -  37 S...  

More info:
All of my failed attempts with red/clear dominoes shown at the end were with M Lamping Dominoes when I did not have any Bulk Dominoes.
Most of the failed attempts were built free standing a short distance away from the hanging board/guide seen in the video.
The highest free standing attempt I was able to achieve with M Lamping dominoes before they tipped over was 27 stories.
The curved appearance is the result of wide angle lens distortion, and these pyramids had no curves.
The 38 story pyramid stood complete and free standing without support for 10 minutes while I moved around it.
The 38 story pyramid took 5 hours to setup.
The guide bar reached it's limit, and it appears as though it touches the top of the pyramid in the video, but it does not.
I wanted to remove the bar to make this clear. The pyramid moved slightly when I stepped next to it, and then began tipping over when I reached for the bar.
I suspect my breath was just enough to tip it over, as the bar itself was not touching or holding the pyramid in place after the final stone was placed.