I am looking for 4 silent chain assemblies.3/8"pitch chain x /2" wide3/8" pitch3.00"pitch dia.driver sprocket[+-], 25mm light interference fit hole w/keyway 6".00 pitch dia.driven sprocket[+-},75mm light interference fit hole w keyway9.5" centersall for 2:1 ratio[can be[3.5"and 7"also 4"and 8"]