Most new brake lining must be cured to reach full stopping power potential. If you purchase loose linings you may have to cure them in your oven. Adherence to the curing procedure will determine how well they work for you. It can be done at home.
Adhesive technology has advanced a bit in the last three decades and the brake folks prefer to rivet and bond the brakes if you say the word "racing." Modern race linings may need to be warmed up to a thousand degrees to get the highest Mu. I have the lining bonded only because the Vincent brakes do not get hot (compared to modern racing brakes running at 2000 degrees).
AM4 is made with asbestos and installing will affect your ability to travel to other countries, your resale value, and possibly your health.
AM4 is a pretty poor performer compared to most modern linings.
GGW (Green Gripper Woven) can be installed in the US by sending shoes to:
In addition to our other brake & clutch relining services we also do relining for all classic cars, historic & antique cars, trucks, and motorcycles.
industrialbrakeclutch.com
They have done shoes for many Vincent owners. I believe that Saftek in the UK was the largest supplier of GGW in the UK.
Just as an aside, the original Vincent brake shoes are not up to the job.
David