a-230

Here is the deal.A motor runing at 3000 with 3.23 gears with a 28 " tire will be traveling at 77.39mph.
[email protected] with 28"=64.39mph
[email protected] with 28"=60.62mph
Your tranny is slipping or your tach is not reading correct,or is on the 6 cylinder range or 4 cylinder range,but something is wrong.This is done with a 3 speed tranny with a final gear ratio of 1:1.A overdrive unit would reduce your rpm by 33%,so your rpm would be 1575rpm.I would check your speedo for its correct reading with a nother car,mrmopartech