This thread will go over the steps to swap a 0331 head. The swap was done on my buddy's 2000 Cherokee. For detailed instructions, I highly recommend using a factory service manual or Haynes service manual. This thread is an overview of the steps required to swap the head.
-new "beefed up" 0331 head from Clearwater Cylinder or Alabama Cylinder
-valve cover gasket
-new head bolts/studs
-195* thermostat and gasket (recommend buying at dealer)
-Coolant and oil + oil filter
-New spark plugs (optional)
-razor blades to clean up surfaces
-shoe box + cover to put push rods in order
-loctite thread sealant
-1/2" 12 point deep socket
-3/8" drive torque wrench
-metric and standard wrench sets/sockets
-PB Blaster or Kroil
-Fuel line quick disconnect tool
The project took 3 days to complete, but about 1 day of that was running around and gathering tools we hadn't bought yet, and flushing out the cooling system. We also took our time and cleaned everything while it was apart.
I highly recommend Kroil, it is available on Amazon, and works much better than PB Blaster. Spray every bolt before removing it. I soaked the manifold bolts overnight as well as the head bolts, and didn't break a single bolt.
I also recommend labeling all of the wires you unplug with tape and a marker, as well as the throttle cables. All of the parts we took off were put in bags and labeled. This made putting everything back on much easier. Taking pictures also helps you remember where things go.
First, we removed the hood for better access to the engine bay, and degreased everything. I also removed the air box. There are three 13mm bolts in the bottom holding it in, as well as a hose clamp on the throttle body.
Next, drain the oil and coolant, and remove the fans as well as the coolant hoses attached to the thermostat housing. Then remove the thermostat housing and thermostat. Use a drain pan since there is likely still coolant in the head.
Next, I removed the belt, belt tensioner pulley, and power steering pump. It is not necessary to remove the belt tensioner pulley, but I did so for better access. The power steering pulley must be removed since it is attached to the intake manifold. Just leave the power steering lines connected and lay the pump to the side.
Next, remove the throttle body. Be sure to label the sensor plugs and throttle cables so you know how they go back together.
Next disconnect the vacuum lines that are attached to the manifold. Be careful with the PCV hose that connects to the rear of the valve cover. It is brittle plastic and I snapped it, resulting in more time needed for a junkyard run.
Next disconnect the fuel rail. You need to first relieve the pressure in the line. Open the gas cap, then press the small pressure relief button on the fuel rail with a screw driver. It looks similar to a tire valve stem and has a black plastic cap over it. Be sure to have rags to collect the fuel that will come out. Then use the special fuel line disconnect tool (can be rented at Autozone) to disconnect the fuel line.
Once the fuel line is disconnected, unbolt the fuel rail from the intake manifold, unplug the injectors (make sure to label the plugs in order), and pull the fuel rail towards you. It will require some force to pull it out, and make sure you pull from the sides, not the middle, so you won't bend it. It will pop out, and then you can pull it out of the way. There will be some fuel remaining inside the rail, so drain it into a pan. I recommend cleaning off the injectors while you have them out.
Next remove the valve cover. Unscrew all of the bolts and put them in a labeled bag. You might need to tap the valve cover LIGHTLY with a rubber mallet to break it loose. Also remove the coil rail and spark plugs. There are four bolts holding the coil rail to the head. Also remove the 2 bolts holding the A/C compressor bracket to the head at this time.
Now you have exposed the rocker arms and push rods.
Unbolt the rocker arms and put them in a shoebox in the same order they came off of the head. Do the same for the push rods.
Now the head should look like this: