The very last 1100 model, born in February 1966, was the 1100 R ("R" stood for Rinnovata). It had a longer, straighter and slimmer line, with a square back and a front-end look not very different from its bigger sister the Fiat 124. In terms of styling cues, the vestigial fins were further suppressed and the simple round rear light cluster from the Fiat 850 replaced the vertical form seen on the 1100 D. At the same time, the larger engine was withdrawn in order to avoid undue overlap with the 124. The 1100 R was offered only with the older 1,089 cc engine, now with a compression ratio of 8:1 and a claimed output of . This engine (with a somewhat narrower bore) had been first introduced in the 1937 508 C Balilla 1100.