Blower tech 101

Thinking about the next project and wanting to put a blower on the dart.I know nothing about them so im looking for some insight.Pros,cons,etc.

671 vs 871 big difference?

Will more than likely use a 440 as the car is set up for it already and i have a
block already prepped.Automatic w/manual valvebody.

Street car,probably limited track use,so it will be set up as a street car.Full tub or mini-tub not sure on that yet,more than likely mini-tubbed as i want to
keep the back seat.

Need some specs.Thanks