I tired, I really tried to make mbc work in modern. And yes there is a big difference between 8rack pox and mbc. I tried infect, but that just costs too much and is meta dependant (but what isn't these days), I tried Necroplasm but that is too slow and now there is this.
Shit worth talking about:
Night of Souls' Betrayal and Curse of Death's Hold: They are the reasons for the deck. The point is to resolve 2 of these and turn Barter in Blood into a better damnation, from here you raven's crime ftw.
Barter in Blood: Basically damnation, often a better one. AND A CHEAPER ONE!
Raven's Crime: This is something you need, you will be, very likely, drawing 2 cards a turn and one of em will be a land, this will turn it into something much better.
Sign in Blood: Ancestral Recall! >D
Wrench Mind: Hymn to Turach! :D
No but I think it's pretty clear, both good at what they do.
Grasp of Darkness: Early game this is gets and later, with curse and night it is also amazing late game.
Hero's Downfall: Maybe you have heard of them, planeswalkers, they exist, you will want to kill them, this is how you'll do it.
Liliana Vess: Either a win vs slow decks, or another curse or all the cards you'll ever need.
Mind Stone: allows for turn 4 win cons and for turn 3 board wipes.
Painful Quandary and Palace Siege: Win cons, Palace Siege is great to keep you alive, even if you have an arena in play and Painful Quandary doubles up as discard.
Phyrexian Arena: DRAW! Which is something you'll need to do, and this helps you do it.
Dread Statuary and Leechridden Swamp: Win conditions, paying 4 mana for 3 damage is fine, especially when you have 10 lands and nothing to do, which will happen, a LOT. As for Leechridden Swamp it is mana for 1 dmg and with 13 black pernaments that won't go anywhere, at least in game one, you have a really good chance to have it online the turn you start to have useless mana is pretty high.
You want to get some early disruption going or go for a turn 3 barter or night. From here you just kill, discard their hand, draw and kill them with something.