New to this site, and hope me and my father can learn a lot.

I was wondering if anyone could answer me as to what transmissions are interchangeable. I have found a 1972 727 that I would like to replace mine with but need to know for sure if it's possible.

 

There are basically two bell housings. There is a big block and a small block. All the big block transmissions interchange and all the small block interchange, but you cant use a big block trans on a small block or vise versa. Also there is a 727 or a 904. There are overdrive transmissions based on either of these but the rules are the same.

 

A couple things to watch out for when looking to interchange transmissions, as noted above. First, make sure it is the correct bell housing for your block, small or big. Second, check the tail shaft length, as the short shaft were generally used in trucks and HD applications ( like Motor Homes ) and the cars generally used the long tail shaft. Next, check to see how the drive shaft connects. Is it a slip yoke, or not?

Here a couple pix of the different 727s that you may find in your search...

 

1st thing you need to learn is it's, "My father and I" not "me and my father".
Kidding, Now to the real question, What are you putting it in? I'm guessing the 66 Fury, right? What motor is in there now, Is it a 66 or later? As stated above there are a few differences such as bell housing and tail shaft. Most likely the 72 you found will work. but the engine size will matter. Also things like the part throttle kick down, a desirable option, started in about 71 or 72 I think. Linkage and levers and the like, should swap to the new trans, as they had several different levers depending on body style and year. Last you will also need to know if the motor is internal balance or not as the flex plate and torque converter will need to match. More info on your project will help us help you. Have fun and good luck. If at all possible go through the new tranny now while it is out, or at least replace the seals, gaskets, and filter. Cheap insurance.