“Compatible” with all Traxxas TRX-4 and TRX-6 models. As seen in this GREAT third-party review by Crawler Canyon on YouTube. Torquey 775 Motor Conversion Kit UPGRADE for Traxxas TRX-4 Scale Trail Crawler. Lots of weight down low. 3S-6S on a Traxxas Titan 775 motor. No permanent modifications required. 1-motor mount for 775 Size Giant Motor. 1-Servo relocation bracket to accommodate the larger motor. 2- 4mm screws to mount the motor to plate. Designed by a professional machinist for great fit. 3-D printer to keep pricing affordable and fun. Will require a larger diameter pinion gear based on your driving style. We are running an 18 tooth on the 2-speed version. We have run this with the Castle Copperhead on 4S and the AE-4 on 6S baby! Let me tell you, that is FUN STUFF! Any questions please ask.