From what I read before doing my gear swap, the quality control on the Ford OEM gear is the best, and that includes the Ford Racing gears. Richmond has excellent quality as well. The biggest advantage to using Ford gears, is that 99% of the time, you can use the original size pinion shim that was on the original gear. I bought Ford OEM 3.73's (which listed less than Ford Racing 3.73's), cross referenced to an Explorer, and I used the original shim from my 3.27's. The tooth pattern was perfect! Just for the practice though, I calculated what shim would have worked, and it came out to .027, just like the original.
1932 Ford 5 Window Coupe Project 521/C6 2008 Ford Crown Victoria LX