Essentially, this is just one big shoehorn.
It will be quite obvious very early on in this video that the engine in this old Impala was never intended to go into a car. The intake, which we are assured is only temporary (so relax), plainly has “Dodge Ram” written on it. The engine is a Cummins turbo diesel, an inline-six of an unspecified displacement or power rating. The engine swap obviously required a lot of work, including the need to fabricate a new firewall and a new floor for the car.
But the result is certainly cool, if a bit unusual.