If I am doing work for a sports service client who had great rankings at first and than they got slapped down as they were seen to have their network of 150 blogs or so on the same server and than I move them to dedicated c class ip addresses will it be the next time they are crawled on the new server that the rankings will re-appear or what will happen?
We can say 100% How Google will take these. Check site for indexing. Remove links from non-indexed or cache removed blogs. Keep links only at quality blogs even you move to a new host. Wait and analyze.
If this really is a network of 150 blogs and the rankings all went down, then I presume your client has a content farming issue. Like nancysmith's note on the changes, I also think it will not help. The best thing to do is to read on posts concerning Google Panda update and how to excuse the site from being hit by it. Or, if the site is already hit by the Google Panda update, here's an article from seoboy.com on how to recover from google's panda update - www .seoboy .com /recovering-from-googles-panda-update/ (just put it together)
Then you may have not been hit for that reason. Are you sure that you are being penalized and that you are not just dancing in the Google rankings. If you are banned or under penalty then simply changing your server is not going to help you. You would have to change the name and start all over for it to make a difference. The best thing that you can do is make sure that you remove your links from all of the blogs that are under scrutiny and get yourself some new links from reputable sites. There is not time frame that it will take, once you are hit, you have to ride out the storm.
I don't think that you are penalize for network of 150 blogs. If your all blogs are independent and have unique content then Google don't penalize your website for linking them. On the other hand if your all blogs are of low quality and have copied content and they all are on same ip where the website is then definitely you will get penalize. I would suggest you to take above points in consideration before going for dedicated c class ips.
If your sites are owned by different people (your sister, dog, etc..) and even if they aren't interlinking is a great way to increase all your sites values if your spreading it out over different ips. You've got some other footprints like link patterns, domain ownership, etc... to deal with but if you use your head you'll be fine.