Darin Davis Writes in:

I took these photos at the 2009 Sandia Vintage Races. I did not get much info on the bikes. The Silver Vincent was out of Califirnia and the Guy thrashed it on the track. The old green triumph#207 belonged to Malcolm Dixon a good friend. He was 74 years old and still racing. Malcolm passed in 2010. He wasa member of British Motorcycle Owners Association in Houston Texas. Thanks Darin Davis

Great Stuff!  That Vincent is stunning.