The Yugo copy of the 128 engine had substandard metallurgy compared to the Fiats of the time. A real killer autocross car in the day required fitting of the 1500cc from an X1/9, with the appropriate head work and a pair of 40 DCOEs. Talk about David vs Goliath situations. It would destroy most cars at the event. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.