Hello all, So I pulled out the center section, (489 ) and counted the teeth . It has 9 on the pinion and 43 on the ring. Sounds crazy high. Like 478-1. Diff is in fantastic shape and spins like velvet. Has the springs/post unit. Should I change out the gears, or try to trade it ? I am looking for 355 or 323. Haven't fully decided due to the fact that I haven't picked out wheels n tires yet. I am building a 69 dart with a fresh 440 /727 combo. BIG project. Thanks.