I thought you might be interested in some pictures of my  1971 SNO PRINCE - GTX-440.  I bought my sled about 4 years ago off the original owner.  It is apparently a "factory racer" built by Sno-Prince in the 1971 model year.  It features a slider suspension, low profile racing seat and a Hirth 440 twin.  Sno-Prince built several GTX440's and also GTX640's.  My sled was the only GTX 440 sold in manitoba.  There is no literature about the GTX 440 in any of the original brochures or in repair manuals.  This sled was an experimental model in 1971 and the technology was then used in the all new 1972 SST models. 

Mine is an unrestored original with all the original equipment.   The motor  
is rebuilt and runs great.  In the past 4 winters i have put about 3000 miles on it with many 200 mile day trips.  It is a blast to ride and will do a top speed of about 60MPH.  If you (or anyone you know) has any more information on these rare GTX models please let me know.