You can try running your own numbers here:
http://www.scriptasylum.com/rc_speed/top_speed.html
but this is what I get:
Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 19
Total Voltage: 22.20
Motor KV: 1580
Tire Diameter (inches): 6.2
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 2.53 : 1
Total Ratio: 8.35628 : 1
Tire Circumference (inches): 19.48 inches (494.74 mm)
Rollout: 2.33:1
Total Motor Speed: 35076 RPM
Vehicle Speed: 77.42 mph (124.37 km/h)
Effective KV Value: 1580
KT constant: 0.86 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...
Edit: If you then click on the gear symbol next to estimated top speed, you'll get a table of pinions vs. speeds that will help you choose an appropriate pinion:
10T 40.75 mph
11T 44.82 mph
12T 48.90 mph
13T 52.97 mph
14T 57.05 mph
15T 61.12 mph
16T 65.20 mph
17T 69.27 mph
18T 73.35 mph
19T 77.42 mph
20T 81.50 mph