I would not use a wheel that small. It looks out of place, and is difficult to steer with. The smallest I recommend is a 14 inch (360/365 mm). The original wheel is 15 inches (390 mm) in diameter. You need one of a few adapters.
Grant makes a GM adapter for pre 91 cars that will fit your car. It must be modified by extending the hole for the horn connector clockwise to allow the horn connector to fit. I used a Dremel with a 1/8 inch mill to carve the metal about another diameter clockwise. There are two small tabs on the inside of the column trim that must be removed, or the trim ring will bind. You also need a 1 inch spacer that bolts to the Grant 3 hole mount, and has the correct hole count/diameter.
Another option is NRG. They make a solid billet adapter that needs no modification. There are 2 sizes, but still need an adapter to give you the correct wheel to turn signal stalk distance. I believe one size (short) needs 1 inch, and the other (standard) is 1/2 inch, but they must bolt to the NRG adapter, and the wheel must bolt to it. The NRG has bolt patterns for the NARDI and MOMO patterns. You may not have to cut the tabs on the inside of the column trim.
Either way, you must remove the clockspring. When you remove the clockspring, the airbag light will be on. You can put a 2 ohm 10 watt resistor across the yellow wire leads under the dash, and the light will go out. If you have a passenger's side airbag, it will still work.
Flaming River Ididit adapter with 5/6 holes may also work without an adapter, but they are recent additions to the available adapters, and I have never used one. They are relatively inexpensive as well.