Don't get all hung up in the number codes. They don't mean anything useful with regards to motor selection. The exception is Eflite once you get up into the Power 10 and larger motors.

The nice thing is that all the manufacturers are pretty much making the same motors for the most part. You can take the size, weight, and Kv off an Eflite Power XX series motor and use that info to find a comparable motor from another manufacturer.