I believe the bellhousing to transmission mounting locations were changed in 47 so it is unlikely this transmission will mount directly to your 40. It will require a different bellhousing or adaptor. In addition you will need to change the rear end just as you would with a T-5 or any other transmission designed to use with an open driveline. Other components used with the B/W overdrive include a pull cable, relay, kick down switch, and the wire loom, in addition to the solenoid and governor which hopefully came with the trans.
Fred
