RE: New Gearbox spins prop Backwards!
In order to use that gearbox, you're going to have to reverse the motor wires. It shouldn't bother the motor. I generally buy my Speed 400's as to how I'm going to use them. For this I'd order a speed 400 broken-in and timed for reverse. I get my motors from New Creations R/C. They do a great job. I have just taken plain speed 400's and used them without being re-timed. I won't use a motor that has been used in a gearbox such as yours in direct drive.