I've got a '92 Regal with the 3800 that I'm going to extended drains on. I bought it with 78K on it. At about 90K I RXd and flushed it. I've just completed a 4800 mile run on Amsoil 5W-30 and have a fresh fill of the same. I'm using the Wix equivelant of the PF52 (oversized). This car is used exclusively for a one-way 54 mile drive back and forth to work for about 115 miles per day. I usually run about 78-79 MPH. Therefore, it sees a fair amount of accellerating from 55-->80 MPH. It's used for very little else. How long should I expect to go on this oil? When should I get a UOA done?