Not without extensive (and expensive) modification
YES, If you know what you are doing.
Yes (...but why?)
no
Yes
Yes
I am assuming that this is not a vortec engine?.......If it is a vortec, they use different angle bolts securing the intake to the heads..........and you will have to get an aftermarket intake to run a carb........If it is not a vortec engine..........go to a junk yard and search out a cast Iron unit form a van..........they are most common........Of course it will be of the spread bore pattern and if you choose to use a holley you will have to use an adapter plate..........If not, a quadrajet will bolt right to it..............
Yes (...but why?)
Yes
You can put the Vortec in it if you have the wiring and ecm to run it. or you could use the Vortec heads and an aftermarket intake and really wake up your engine. The vortecs use a roller cam.
This one will take some digging since Chevrolet introduced two types of 5.3 liter engines one being a Vortec and one not. The earlier Vortec put out app: 30% less horsepower than the 2004 model, hope this helps
If you attempt to put a vortec engine into a vehicle with a NON-vortec computer, you'll have more problems than you care to deal with.
Assuming that you would use the intake and the injectors and the computer from the 2000 and they are both vortec.