even roughly, no one can give you accurate advice unless
we know what kind of pit, what temp you cook at, what
the pig ways.
butterflied pigs, which are the status quo in North Carolina,
will cook at a different time than a whole hog propped up on a grill Hawaiian style, at the same temps.
That said, an 85 lb hog butterflied, cooked roughly at 250, will take roughly 8 to 12 hours.
That said, it's done when it's done. Lean pigs cook faster, fattier
pigs cook slower. There's no real way to guess how long it takes.
It's just done when it's done. You can use therms or you can just pull
bones and know when it's done.
the good news is, whole hogs are easily held for hours on low heat
after cooking, if you don't drain the fat out. It's actually better in
a non- comp setting to let it rest and cool and little, before piercing
the skin and letting the hot grease out.