I may be wrong but I think the 4 x 98 has been a Fiat standard for decades, think the 850, 128, X1/9 and other used it (of course in 13" and 14" versions). Did they ever use any other? 4 x 100 does sound familiar, was that used on Alfa's?
1973 Fiat 850 Sport Spider
1977 Fiat X1/9