I didn’t see anyone directly address OP’s mention about the possible slipping sleeve... Correct me if I’m wrong, but a slipped sleeve would get louder as the engine heats up, expands, and let’s loose the liner. He mentions that the ticking noise goes away after driving for awhile. Also, while neither of my discos have had slipped sleeves yet, it’s been described here on the forums as more of a bass-heavy thunk-thunk rather than a tick. FWIW. ¯\_(ツ)_/¯

 

The tic is probably related to the external head gasket leaks.

 

If a sleeve has slipped, he will be a able to tell once the heads are off.
It will leave an impression on the bottom side of the head gasket, like a ring around the cylinder hole in the gasket, where the top of the sleeve has been hammering into it.

 

The slipped sleeve tics are usually only audible at idle, they go away with speed because the pistons are moving too fast for the sleeve to keep up. They also typically do not start until around 190 degrees. You have to verify it is not a low oil pressure condition first, which can sound the same with ticking lifters.

 

So we started the process today and made great progress. Everything has gone smoother than expected. We followed the AB video on head gasket removal and have everything down to the headbolts removed (had to go buy a breaker bar), but they all came out fine. Everything I have seen says that the heads should just come right off, but neither of these are budging. 3 long bolts and 5 short bolts removed from each side. Tried rubber mallet, progressed to block of wood and a heavy hammer, but neither of them is budging. I wasn't sure if it was ok to try to pry a screwdriver in somewhere or not, but we have applied a pretty serious amount of force and they feel like they are still bolted on. The AB video was good about tips and tricks for sticking parts, but this one wasn't even mentioned. What are we missing?

 

Do not pry aluminum scars and gouges very easily, Rubber mallet is best try from the intake manifold side then lift from the inside towards the outside (fender)

 

Some additional notes when you strike the rubber mallet, try to strike in an upward direction - from the lower portion up. Try the front corner, you need to get the gasket to let go.

The other thing you can try is a piece of wood in the intake port - if you do this it has to go in deep. And pry up, I would put a couple of long bolts in the top just in case the head let's go all at once when you do this.
Once you get the corner up a wood or smooth plastic wedge worked along the edge get it sort out if required
Some them get pretty stuck, just remember only a couple of short positioning dowels are hold the head in place

 

It is ten bolts per side, you still have two short bolts in there, that is why they are not budging. My guess would be you have not gotten the two out on the ends that are deep in the heads. Get those and they will lift right off.

 

Listen to the AB video, you need a universal jointed socket for driver rear head bolt....

Don't re-use the head bolts. They are a one time use TTY bolt.

 

Sheeeesh.... We had gotten all the small bolts out, but the two large ones on the ends were down lower and pretty much submerged in oil. Never saw them. I'm guessing that is going to make just a tad bit of difference in pulling this off.