Muscle Car/Hot Rod/Racing 2-Wheel Drive 2/3-Speed Automatic Automatic 3-Speed TH 400 4" Tailhousing - Electrical Speedo. Replaces 4" tailhousing. To replace 4L60E with factory electric speedometer. Install price - $750.00* *Typical install & drive shaft modifications. Does not include any modifications to exhaust, transmission tunnel or any other custom modifications that may be required.