1965 Dodge Dart Charger
This site referenced above shows the 273-2v as a code 31 with the 273-4v as a code 32.
The '62-'65 white book shows a 273-2v as a code 30 and a 273-4v as a code 31.
The '66-'68 white book agrees with the website.
I managed to locate a '66 Canadian order guide which showed the 273-2v as a code 31 and the 273-4v as a code 32.
My '65 Canadian order guide is incomplete and shows no "L" series cars at all.
Having said all of this, I'm voting for a '65 273-4v to be a code 31. All sources agree that an automatic trans for a V8 is a code 395.
FWIW, there is only a small mention of the 273-4v in the US Dodge data book, and virtually no reference to the 273-4v in the Canadian data book. BUT, the Canadian MVMA does show the 273-4v and lists all of its specs.