I am at a tipping point with my car. I have spent quite a bit of time undoing the sins of it’s past. It has a new zz454 crate motor, and a rebuilt Muncie M20 4 speed. Working front to back, the next step is the rear end. It has a 10 bolt 355 with an open diff....horrible. I am ready to swap the rear end. The horsepower and the torque are good...I just don’t feel like I am getting the power to the ground. I am thinking about a Mosier 9” 373. I am just looking for some advice as to the best way to make the car faster. Would my motor/trans/rear end setup above make a significant difference? From what I have read, the combination working together means everything. I am not prepared to do something different with the tranny, but I feel like it’s workable. The suspension is basically stock. Any input would be much appreciated. Understand I am a bit of a newbie when it comes to A lot of this.