The following was sent to us from Gary Kunz.  Could be good info for you if you have a 75-80 Triumph!

The testing facility will enter the year of all 75-80 triumphs as 74 in their equipment so the vehicle will be tested to the 74 standard.  They will only do this though if you have the letter which is why I thought to post it on the web.  Share it with everyone.  I only found out about it after I failed my initial test and called for an extension.  I called early in the morning, before the receptionist arrived, and talked to someone who know about the letter so he sent it to me.  He did indicate that when the letter first came out they distributed it to all the car clubs.  When I had my car tested the second time the tester knew about the letter but couldn't volunteer the information.  You have to have the letter in order for them to enter the lower year in their equipment.  The pre 74 standard is 5% CO vs. 3% for the post 74 and 900 HC(ppm) vs. 700HC(ppm) so the difference is significant.

Click here to open a copy of the letter