NOS Mopar # 1673646 supercedes to # 2863494 flywheel ring gear for 1969 Plymouth Road Runner with 426 Hemi engine and manual transmission.  Item has 172 teeth, has number 1673646 stamped into it and measures 13 1/2 inches inside diameter, 14 1/2 outside diameter end of tooth to end of tooth. Also fits some earlier 225, 361, 383, 413 applications including some truck and marine and industrial. Check your parts book for exact applications. Use this in your Plymouth Belvedere, Satellite,  Road Runner, GTX,  Dodge Coronet, Charger, R/T, Super Bee.