Slant 6 Turbo 68Dart Project

Poor road manners would come from no choke, unheated intake, and very large carb on a engine that (naturally aspirated) could use half of the carb most likely. Also, poor fuel distribution may have a part in it as well. Possibly doggy off boost by means of low compression, very high geared? Bill and serj might be able to tell you more on driveability issues, I'm just spitballing with educated guesses.