That engine is a 3306 not a D333c and there is quite a bit of difference between them.
This is the problem with swapping motors from one use to another.
Bad Bob
I completely agree, which is why I said I wouldn't swear to it.
Further digging has revealed that the 66D prefix Industrial Engine is similar to the engines fitted to some models of track-type tractor and track-type loader of the same era. It started life as a D333C when first built and then switched to being a 3306 from S/N 66D8891.
So 66D31288 is confirmed as a 3306 even though the latest version of SIS incorrectly describes all the 66D product as a D333C. This is a lack of flexibility in SIS2.0 that legacy SIS did not have. Progress I suppose.....
I also found a Steiger Tractor data sheet for a 3306 engine. Possibly this data could be more accurate. Again there are no guarantees but seeing as the document was produced by Steiger and the 7N3389 Arrgt was only built for Steiger it stands a chance of being somewhat close. An Intermittent Rating of 250 BHP @ 2100 RPM.