That's fast. Good job. I could match that rate by going all out on a tiny 50 foot high climb, I think! Edit--yep, on a previous ride, after riding downhill, I hit the base of a 40 foot (!) hill going 28 mph, and got a VAM of about 1100.

On the BF's Tour of California Mt Diablo thread, the local riders were amazed by the new record set that day. Here's the Strava segment link, showing a VAM of 1435 for an 11 mile climb. And that's after 82 miles of racing! Those racers are on some whole different level.