It's pretty much all been said.
Based on my experience with a similar '72 304 Wagoneer, I agree that AMC's brakes, distributor, clutch linkage, and wiring were junk as described above. I'll add that on this one, the gas tank leaked at its seams ("they all do that" - dealer) and the smog-pump tubes in both exhaust manfolds were rotted when I bought it so it needed new manifolds to pass smog inspection before I could register it.
This Wagoneer was apparently special order for the military. No power - anything, and a granny 4speed that I was told was the same as used in a Ford 3/4 ton. I could always count on 15 mpg, towing or not, it didn't make any difference.
This was from the era when a car was designed to last 100k miles. I sold it at 135k after nearly every subystem (except the running gear) was shot. The last straw was when I hit the low-beam button and lost all lighting, just as I met a logging truck unexpectedly on a tight blind corner with both of us moving a little faster than we should have been. Once I squeaked past him I had to lock the brakes - in the dark I had no idea which direction was pavement and which was cliff. (Up by Brown's Valley/Strawberry above Marysville for those of you who know the Northern Sierra back roads.) It was a fun rig but not reliable enough for a daily driver. After it got broadsided (while parked) I got rid of it.
Here's a problem and solution that is common to the 304 and the larger 401, where I encountered it in a later Wagoneer: The wire from the points to the distributor's external terminal can chafe and ground inside the distributor under certain combinations of vacuum and centrifugal advance. This throws an extra spark at the wrong time and in the case of my 401, I think that had broken the rings or bent the crank. Replacing that wire cured the misfiring, but it remained near impossible to start due to internal engine friction even after all new starting components. That's one of a couple of vehicles I've given up and sold shortly after buying it.
Photo: Jeeping with the Wagoneer, waay back in the woods on an old mining-camp trail. Truth be told, my later '88 Trooper did a better job in that terrain. But neither ever broke anything back in the woods.