You would think that replacing a '65-'66 steering wheel would be as easy as removing the old wheel and sliding the new one onto the steering shaft. If you're replacing a standard wheel, that's pretty much the routine. But if you're installing a wood wheel, as found on the Interior Décor Group (Pony interior) option, the procedure gets a little tricky due to the wood wheel's use of two horn ring contacts, which must be assembled inside the steering wheel collar with insulator "feet," screws, and springs.
You can still get the nicest...
You can still get the nicest reproduction wood steering wheel on the market from National Parts Depot. Unlike a newer reproduction that's available as a kit, the original wood steering wheel reproduction is identical to the deluxe wheels used in '65-'66 Mustangs with the Interior Décor Group (Pony) interior. NPD offers it as a wheel only (PN 3600-5A) for $186.95.
National Parts Depot's reproduction of the factory wood steering wheel is a great way to improve a Pony interior or to upgrade a standard interior from the plain steering wheel to the luxury version. In Merv Rego's case, he wanted to replace the worn original wood wheel in his recently restored '65 K-GT fastback. With NPD's best reproduction wood wheel (PN 3600-5A), Merv's steering wheel looks as good as the rest of his red Pony interior.
We assembled and installed the new NPD wood wheel at Merv's Classic Creations of Central Florida shop in Lakeland, Florida.

This illustration from the...

This illustration from the NPD catalog shows the various parts of the wood steering wheel and how they go together (image copyright National Parts Depot).

Begin the assembly by sliding...

Begin the assembly by sliding the trim collar onto the horn ring, as shown.

Push the plastic insulator...

Push the plastic insulator "feet" onto the inner and outer horn ring contacts.

With the horn ring and collar...

With the horn ring and collar upside-down, slide the inner horn contact ring into the center. This can be trickier than it looks because the plastic feet can fall off.

Next, slip the outer horn...

Next, slip the outer horn contact ring into place, once again being careful to keep the feet in place.

Once in place, the pair of...

Once in place, the pair of horn rings should look something like this inside the collar. At this point, they are not secured.