I've tried Bill's Tech site, and did not find rumbleseats description of how he did his Columbia. Maybe I missed it?? I scanned through some of Paul's stuff (at the bottom of the site). So, to try and address a little of Tom's question... This is part of what I think I remember (and keep in mind, my memory is fading). I think Paul based his Columbia on parts from his 34 rear end, and Columbia parts from a 46 or 47 Ford. Machining and Fab skills required. I think he used the left 'bell', as is. This would be a 34 bell, same as late 32. I think the right bell is a combination of the 46/47 Columbia bell, and a 34 bell, which he put together. I think the center section (banjo) is from the 46/47. My recollection of the axles, possibly the 37-40 type (inaccurate, see edit below), as I recall he modified the outer ends slightly, to compensate for length. Total axle width must have come out just slightly greater than stock 34. Paul's car, BTW, is a 34 roadster, so doing this for a 32 would be very similar. I'm sure I've missed something, and I hope others will correct me if you find errors.
Somewhere, I think I have a copy of what Paul wrote. If I can find it, I will either re-post, or edit this post.
JMO
I found this, which I believe may be the info requested. I have no record of where I got this, or date it was posted....
Since you asked: My Columbia is an electric/vacuum unit from a '46. The Columbia overdrives are wider beginning in '35 and are wider than the ones used in late '32 thru '34 Fords.
To make everything fit was fairly simple once I got into it. Changed the complete center section (with the 3.78:1 rear end gears) to a '35-'48 since center sections beginning in '35 are wider and the '34 won't accommodate the wider gears. (Some guys machine shims so they can retain the stock, and narrower,'34 center section. I've never done this, but understand it's being done frequently.)
The wider '35-'48 center section makes the stock '34 axles too short by 3/8" on each side. I used the spider gears from the '46 and made longer axles using the '46 axles and shortening them so they were 3/8" longer than the stock '34 axles. This required machining a few new threads and lengthening the taper and keyway. Sounds like a lot of machining, but only took about 40 minutes to set them both up and machine everything.
The right '34 axle housing was cut about 4" from where the right wishbone connects. Using the outer section of the '34, a friend grafted the right side inner axle housing (with the Columbia section)to the outer section of the '34 so the newly created right axle housing is exactly the same length as the stock left axle housing. The stock '34 wish bone bolts up on both sides as do the brakes and backing plates previously used. Then it's simply a matter of bolting everything together. It's worked good so far.... and that's been somewhere around 100,000 miles. Hope it stays glued together on the runs planned this summer. .....rumble seat
This same info is buried within the BillB reference info for Rumble Seat, mentioned in other posts here. Click on 'Gears', then scroll down to a paragraph titled Columbia Overdrives.
