Can i motor swap a 3.4l dohc to a 70's 445ho in my 1996 grand prix gto?

Sure you can swap that motor as long as it won't be registered in a location that requires emission inspections as it won't pass. But as they say there may be loopholes in your area. From a strict mechanical viewpoint you can do the swap as long as you do all the fabrication needed such as converting it to rear wheel drive and replace parts like the :trans motor mts wiring among others

You can do it, seen it on some cars but not sure why people would sink that kind of money in to a '96 Grand Prix. I think I would go old school & get something older. you have to redo the chassis, frame & other stuff since your no longer running a crooked engine anymore but the engine they had was shoved in longways so you will have to redo the tranny mount & get a tranny to bolt to it as well with the rear drivetrain