F1R lists Rad Dougall's car (entered by Cassani Racing Team) as an "RT4", but chassis "RT2-181". This was actually entered as an RT2 in 1981 for Winkelhock, by Schafer Racing.
As Chris always says, we can't take F1R's 1970s-80s stuff as Gospel, but may be a starting point point for input from someone...?
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