I just had one come in here, purchased locally to feed a Chevy 350 crate engine making 290hp.
All I can tell you guys is that they copied a 1979-80 Chevy truck carb, and did NOT make the needed changes to make it work correctly or user friendly.
Right to start with NO ONE wants the charcoal canister 3/8" vent in the front, and when you have E-choke the fresh air supply tube in the rear of the airhorn is NOT needed.
The rear pull-off doing both functions is not a good set-up either. They should have used the front pull-off model instead.
The parts they used are horrible, especially the accl pump, so plan on upgrading them.
Internally they have screw in IFR's and a few other mods to make them easier to tune, but overall it's not close enough out of the box for the average hobbyist to work with.
I also had one of the early divorced choke models come in and it took me three tries to get it dialed in for the heavy cammed 406 SBC on the customers Chevelle.
I'm with Lars on these carbs, you'd be a lot further ahead to just buy a nice original core and build your own......FWIW.....