Okay, going to assume you're not familiar with the stock pre-49 passenger rear ends. Rather than the open drive shaft you're likely familiar with from more contemporary cars old Fords used an enclosed drive shaft from the trans to the rear end. It was enclosed in a housing that swiveled at the end of the trans, and bolted "solid" to the rear banjo, it is refered to most often as a torque tube since it limited the rotation of the rear end from the effects of torque. Ford wasn't unique in the use of these as Chevrolet, Buick, Olds, and others employed them too.

If you use the pre-'49 trans it will accomodate the torque tube. If you use one of the other transmissions mentioned, they use the more conventional open drive with the splined yoke to allow for movement in front, and exposed universal joint in the rear.

For early Ford type setups you can get an open drive rear banjo unit from a 42-7 Ford pickup. Or there are after market units made to do the same thing; http://www.hotrodworks.com/Openconv.htm
If you, or someone you know are a good machinist this should give you inspiration, otherwise it is a decent graphic to put a picture to these words.