I remember a post many years ago in which the OP swore that his fathers 65 dart (if I remember correctly) came with an orange 273 from the factory. The car was in his possession and that the motor had never been touched. The post went on for quite a few pages until someone suggested he remove the alternator mount. He came back and sheepishly said the color was clearly RED under the bracket and the motor had evidently faded to an orange color over time.
I was there when the cars were new and bought many in the mid to late 70's for 50-$150.00. Most all ran, some fairly well. I am sad to admit I parted most of them out as the parts were worth more than the cars as a whole. Some had OMG, a rust bubble behind the RR tire. Being in the rust free land of plenty Bay area, that definitely deemed is as a scrapper. Did have one that was pretty crusty. it had lucas headlights and voltage regulator. that was a bit of a curiosity until papers found under the back seat confirmed an officer in the USAF had it over in England had been to for a while.

Not trying to start a peeing contest just stating what I know from back in the day