A steering wheel adapter is available from www.grantproducts.com for Grant steering wheels. You might be able to order this item from Pep Boys or some local auto parts store. It might be possible to modify the adapter or your steering wheel to make the whole deal fit in your car. Adapters are or were at some point available for Momo, Formuling, Nardi, Personal, etc steering wheels. one of those might be a perfect or closer fit. Try one of the fancy accessory shops in Car and Driver.

Sixto
91 300SE
81 300SD