Off road tires on a Crown Victoria?

I have a 2011 Crown Victoria P71. I've always wanted to put some off road tires on my car but didn't want to buy the wrong tires and rims for my car. I was looking at buying some 17" rims for Ford (from what I've seen those are the right size rims) and I wanted to get some off road tires on it. The main questions I have are would off road tires actually fit on my Crown Vic p71 and are there any meaty/Off road tires that would just fit on my regular rims?

Have a 1982 200 Ford inline 6, It idles perfect And quiet, when you accelerate it gets a good amount of power for about a second then?

Starts losing power, if you floor it, it will die. Starts losing most power at half throttle after that it starts to hesitate. Has a new carburetor, timing is good, advancer working, new spark plugs, fuel pump, filter, pcv valve, vaccum lines good,

Added (1). Ah I forgot to mention it runs better with the choke about 3/4 closed, no diaphragm for pump. It has original electronic ignition.

Ford Transit Custom Base?

The Bluetooth on the Ford Transit custom Base model allow you to play music through the van as well as phone calls?

How would I register a care that's missing all of it's paperwork?

My Uncle gave me his 1967 Ford Custom 500. We've restored it and it's like new. The only issue is putting the car in my name and registering it. It hasn't been registered since 1980 and we have none of the paperwork for it. It's been missing for years. We live in California (if that matters). What do I need to do to register this car?