From the Wikipedia entry:
"Based on the prototype Abarth 030, the Montecarlo was known as the X1/8 (later the X1/20) while in development, and was intended to be a Fiat-branded 'big brother' to the Fiat X1/9."
http://en.wikipedia.org/wiki/Lancia_Montecarlo
"Based on the prototype Abarth 030, the Montecarlo was known as the X1/8 (later the X1/20) while in development, and was intended to be a Fiat-branded 'big brother' to the Fiat X1/9."
http://en.wikipedia.org/wiki/Lancia_Montecarlo