In case it wasn't clear, the cinder block "box" should be on TOP of the ground, not inside the pit -- you want the coals to be a few feet below the pig. And the layer of coals should only be a couple inches thick. Sorry if that was confusing!

laughy laugh laugh

WAY too complicated.

Heather you do know this is supposed to be primitive fun don't you?

I have actually roasted a whole pig in the ground.

All you really need is:

the hole
buncha banana leaves, get these where you can, try and get a pickup truck sized amount but really you do want to have 5 or 6 layers of these
3 large bags of briquets. The pig doesn't care if the bags say safeway
7 hours of cooking time
meat thermometer

thing is it is impossible to overcook a pig this way. just keep the pig protected all the way around by leaves, keep the charcoal coming and flip the pig about 3-4 hours through and reassemble your fire. This part is better done with 3 people, 2 if the pig is small.

keep the pig protected
keep the heat on, after about 90 minutes unwrap and check the temp of the pig at a couple of places. Should be about 170 in top and bottom. And if it isnt, double up the charcoal

The hardest part will literally be patience as the smoky aroma will wear you out its so good.

Just smoke it for a couple of days over Strawberry Guava, wood.