The adapter from BME is 40mm back to face and comes with the timing ring and magnet. The adapter from Brillellicustoms.com is about 50mm back to face and also comes with a timing ring and magnet. They also sell a very nice set up for twisting and installing your carb. On their site under conversion parts page two. Also on the sensor bracket, it does not need to be adjustable since the timing ring rotates 360* you are able to mount it anywhere convenient and set your timing anywhere you wish.