As you know, if you own a 7-Litre, you are able to enjoy factory disk brakes that were standard on the model.  These brakes were Kelsey Hayes (KH) 4 piston units mounted on the front.  The calipers on the spindle assemblies were rather large, which required a larger wheel to fit over them.  So, Ford provided special rims on the 7-Litre cars that are different than the standard drum brake versions of the Galaxie.  Actually, the external wheel diameter is not larger than the standard Galaxie wheel, but it has provisions that allow the wheel to fit over the caliper assembly.  Both rims are 15 inch.  A 7-Litre wheel will fit any standard application Ford rim, but the Ford rim will not fit the KH spindles.  The KH spindles are unique enough that it would be difficult to fit aftermarket wheels over them if you had the interest.  KH spindle assemblies were used on disk brake versions of 66-68 Full Size Fords, Mercurys and Thunderbirds.

So what do you do if you need a wheel to fit your 7-Litre and you’re not sure where they are from?  At minimum, you would need the special rims to fit on the front of the car.  The back wheels will accept standard Ford rims, and for sure you’d want one in your trunk as a spare just in case you flatten one of the front tires.  There are a couple quick visual methods to tell a KH wheel from the standard.  In the photos, you can see views of both the KH and standard wheel.  The KH wheel has a full inner hub to outer rim weld bead all around the circumference of the wheel.  The standard wheel has the typical 4 slots around the same bead.  Both wheels are 4.5 x 5 pattern with the same diameter hub opening.  You’ll also notice the visual differences in the bolt pattern support and hub cap bosses (3 on KH vs. 4 on Standard).

Slotted Beads

Backside views show the differences more pronounced.  The significant difference is in the amount of space available on the inner diameter of the rim.  The KH rim has a pronounced width offset that is not present on the standard rim. 

Both rims have the same offset, as you can see below, roughly 4 7/8 inches.

The side view shows the difference in rim thickness.  Overall width of the standard wheel is about 6 inches, and the KH is 6.5.  The important area is the wider offset in the area marked, approximately 2.5 inches.  This is what allows more space for those big caliper assemblies.

The photos hopefully are helpful in your ability to identify a 7Litre wheel.  If you were at a swap meet and found candidates for your 7-Litre, you can take the shown measurements to confirm they would fit.  If the rims measure up, and of course are not rusted out or bent up, you can feel confident on your acquisition.