How interchangeable are mopar steering wheels? Can you install a 66 wheel on a 69 column? or a 72 wheel on a 68 column? I also noticed most aftermarket wheels seem to be 15" in diameter while factory wheels are usually 16". My limited google research indicates that the 70 wheel is 1/2 larger diameter than the 69 and earlier (non tilt models) in order to accommodate the ignition being integrated into the column. It sounds like the spline count is the same...has anyone done this?

Thanks in advance.

As best as I can explain it, there are eras of steering wheel fitments, and then you add trim matching between the column and the wheel. This becomes important between many tilt or non-tilt columns/wheels.
I can't give you specific beginnings or ends there are also differences between truck and car wheels, to some extent. Sometimes, there were model to model differences.

The early Mopars had a hollow column and the horn wire ran through the column. The hollow column is a larger diameter so the newer wheel hubs won't fit those early columns. Those ended somewhere in the 62-63 time frame.
The next era would have ended around 69-70, or when the ignition moved from the dash to the column. With the lock and switch in the column the column diameter got larger, and those wheels grew latger at the column contact point.
The addition of the tilt caused some issues in the early tilt column years, until the tilt and the non-tilt became uniform in diameter, probably the end of 73/74.
Things bumped along pretty well until the air bags came out starting in 88, but not everything got an air bag until around 93. The air bag column has everything different from a non-air bag column.

After the hollow shaft went away, the steering wheels may well fit the steering column shaft, and the spline count, but things like the bottom of the wheel might not fit around the column, the horn ring may be different, or the turn signal cancel pegs might not work. The interface between the top of the column and the bottom of the wheel might not work well together.

I believe the steering wheel adaptors for aftermarket wheels fit columns from the mid 60s up through the early 90s, with a few exceptions thrown in for good measure. The aftermarket adaptors have generic connections for horn function and turn signal cancelation. and a cover adaptor to blend with the top of the column. The bottom of the aftermarket steering wheels are all flat and flush with the bottom of the wheel where the adaptor attaches.

probably not what you wanted to hear, but this has been my experience over the years.

Good info! I was just curious because you don't often see swapped steering wheels between years. I really like the look of the early 60s style with the chrome horn ring.

The main change I know, was on 70 when the steering column diameter becomes larger to accept the ign switch. This make the pre 69 steering wheels won’t match with post 70 columns, and of course, backwards.

To clarify the above, newer wheels will attach to the older column, but the cosmetics are off due to different jacket diameter.

I have an 83 truck wheel on my 69 column.

ruderunner - do you have any pictures? thanks!

Nothing handy right now. But basically the collar at the base of the wheel is larger diameter than the bowl of the column. It's not a huge difference but noticeable.

Cancel cam and horn contacts matched up.

64-69 will interchange. i put the original wood grain wheel from my 69 charger on my 64 barracuda. [my old man kind'a bent it with his lip when he crashed the car hard ! ]
in 70, the ignition switch went into the column. 70-78 [for sure] will interchange, and this includes trucks. i put a 74 chrysler wheel on a 76 truck because it was a smaller diameter, fatter rim, looked better, and the horn hooked up just like the truck. this is only the non-tilt columns of these years.