My car is in storage not near my house, so I can't go measure any time soon with extra effort so it is easier to confirm with all of you.  I need tires for my 56 before I can get it on the road...and sometimes while looking on craigslist I find tires mounted on late model wheels and I have fun imagining different style wheels on my car....but without knowing the bolt pattern (or backspacing etc) I can't take any of my day dreams too seriously.

I understand if I should be forced to go measure my own car...I will eventually do that but it is cold and sloppy up here in Wisco and the storage garage is unheated so I don't really have a desire to go start work on the car quite yet, and I'm too lazy to drive out there just to measure the wheel bolt pattern.

My '56 bird has 5 studs on a 4.5 pattern - so does your sedan. The front suspension parts are identical to the sedan and often - the closest point of contact turns out to be the upper ball joint on the front a-arm. Next time you are near the rascal - take home the spare (assuming it has all the same rims/tires). By having the size and shape of what you already know works - you can often project what other combinations will clear on the inside as well.

My t-bird wheels (OEM) had their mounting face offset 1/2 inch to outboard from the centerline of the tire and rim. This moved the inside sidewall inward a half inch toward the upper ball joint. So it follows that using a rim with a centered mount would allow more room for a wider rim/tire combination - so long as you clear the sheet metal on the outside. Turns out that room is available - its not quite the close clearance of the inboard side.  

The car is up on jack stands, so I brought all for wheels home along with the dryrotted bias-ply tires that are mounted on them.  I was about to stop by walmart and just get four new tires mounted on the original wheels, but boy a cool set of chrome rims would look neat on the patinaed green and rust old car...a cool rat-rod look.  I keep thinking I might find some wheels on craigslist that would work that would come with useable tires already mounted.  But worries about backspacing and rim width and all that are making me think the most straightforward route would be to just use the OEM wheels, plus I have all four OEM hub caps which seems cool.

Is there a common late-model OEM wheel/tire combo that are straight bolt-ons for these old fords?

Well it sounds like the 225/70s mounted on 15 x 7 ford wheels I found  are too wide then.  What if there was less back spacing so it pushed the whole tire out away from the ball joint?  Do you start running into the fender with the outside of the wheel?

Those turbine wheels should fit. I am running 16" x 7" rims (2000 Ford Explorer) on my 56. They have a 4.5" rear back spacing. However, if you are running stock drum brakes up front, you will have to use 1/4" wheel spacers (longer studs) to clear the upper ball joint. I did this for years with no fender rub and 215 /60/R16's up front, 225 /60 /R16's back.

When I changed to Granad front disc, I was able to loose the 1/4" space. Thanks.