I am looking at a 97 F150 4x4 with the front of the motor pulled apart.
The left side chain had broke. it was laying down in the bottom.
The owner said he drove it in the garage running on the right bank only.

Is the 4.6 an interference motor?

Or do you think I can just put a new Chain kit in it?

ALso if the motor is severely damaged,
can I swap a 5.4 in it with just an ECM change?

 

yes it is an interference motor. Some of the valves and/or pistons are likely damaged.

 

You might not need an EMC change. Go to Advance Auto and they will print out what computer will run what engine. Many EMC's will run multiple applications. The 4.6 is not worth fixing. A simple online search will yield many shops that will send you a reman 5.4 with a 36 month warranty and unlimited mileage for $2500-2900.00 and free shipping including your old core back.

Mikey