Can anyone help me with my speedo being out. I have had the speedo professionaly reconditioned, new cable, running a 302W, C4 and BW Diff with 3.50 (?) marking on the crown wheel. (thought the diff was 2.93 by rotating wheel and counting). After all that it is still out about 15 mph at 65mph, speedo show 80mph however at 37mph spot on. Tyres are 215/65/14. This has been bugging me for some time now and i just guess the speed but one day will cop a fine .

mate call super roo in W.A tell them all that and they will send you the right one they are a full bottle on it and have all the different cogs you can get... number is 0894973186