2k vc

This list could work. The main problem with zombie only lists is that while they can bog enemy units down, that is all they do. You will bleed combat resolution so fast that your characters could be affected very quickly. And having only one combat character, you don't have the ability to balance the rounds of combat so you may end up losing by 10+. I would suggest swapping out the tomeless engine for a terrorgheist or dropping enough zombies to give it the tome. That way you will have a huge +2 to cast bubble, which will make your magic, winds rolls aside, much more reliable.

I would advise you to actually go down to 3 units of 20 zombies, and look at having some kind of higher strength unit, Crypt Horrors or Ghouls work well with the Engine and give you something that offers a little more offense. You may also want to consider taking the cursed book, to give your opponent something else to think about in the magic phase. Spamming Invocation and loading up on zombies can work, but you have to have something that can punch back. Spirit hosts are a good hold up units, but as with zombies, they will simply crumble from combat res.