Will a complete 27-27 rear axle, drive shaft assy., and radius rods bolt up to an earlier-21-22-23-24 T chassis if the 2 large drum axle housings are swaped out for the earlier small drum housings?
The 26-27 radius rods are shorter.
I have a '27 axle as is under my 21, no changes made. It fit like it was meant to be there
The internal parts are much the same. However, unless you want it to look original, you can swap the entire assembly including the large drums.
I put the whole big drum ruckstell rearend under my 14 roadster. The big drum rockies look better than the flat drums for the small drum rear end and I didn't have to stack drums to make it work. I don't remember which brake rods I ended up using.
The '26/'27 large drum brakes require a shorter brake rod than the '09 to'25 smaller drum brakes do. About 1 inch shorter. The earlier brake rods require a slight offset in them to clear the radius rods. The '26/'27 brake rods do not have that offset.
Rocky mountain brakes take a slightly even shorter brake rod. Also without a major offset.
There certainly are good reasons to use the larger drum '26/'27 rear end in earlier cars. How can better brakes be a bad thing? And it is still a model T rear end. The fact is, it doesn't even look bad. But some antique automobile people (including me), prefer to keep their cars more correct. Everyone needs to make those decisions for themselves. Then again, I have to admit, my '24 coupe has a '26 rear end and brakes. It was that way when I got it. I do consider changing it back to correct. But have no plans at this time to do so.
Internal parts changed only very slightly from the mid-'10s through 1927. ALL external parts changed more than a little during those same years. Most of those external parts will functionally interchange. Except of course, the main rear housings themselves, and the radius rods. As Steve J said, the '26/'27 radius rods are shorter.
Drive carefully, and enjoy, W2
Like Wayne I would prefer my 14 to remain as stock as I can. But after spinning off a pinion key I thought brakes would be a good idea. I had the late ruckstell with rockies laying around so I just put it in the car. My car can be stock in about an hour and a half, two hours if I replace the modified brake pedal.