Which advance curve group do I use? Matt May 23, 2018 16:02 Follow The “A” curves are for relatively stock motors and those using bolt or accessories (carburetors, exhaust, etc.) The “B” Curves are used for motors with increased compression and require a slower rate of advance. Related articles What is the best method of activating the retard mode on my Honda Valkyrie with the D3K1-1 ignition and a supercharger? Comments 0 comments Please sign in to leave a comment.