Hi. I am an engineer by education and have been taking content writing, translation, and a/v transcriptions related projects since past few years. I will do the required conversion all by myself, without the need of any OCR.
I need you to understand that whosoever you give this project to, but when it is read using OCR programs, the conversion is going to have a lot of errors. Wherever the OCR may fail to read, it may put in some gibberish words in between the sentences. Now, imagine what it can do with those 350 pages worth of content. An OCR-read conversion will then require you to hire a proofreader and editor once again who will then attempt to refine all that text to something meaningful yet again. It is, therefore, recommended, to be converted manually by a careful typist with good English and typing skills, and obviously a little common sense.
I can offer you that, Sir. Hope you give us a chance to work together and come up with quality work. :)
(Please feel free to contact me via messages and further discuss about the negotiable pricings for this and any other projects you might find me fit for. Also, if you need to see work sample, I might be able to provide that too, Sir.)
Thank you. :)