I'd say do it yourself, you'll save money, and end up with a lot more pride in the finished product. If you have an Oliver Service manual, it spells everything out in great detail as to what needs to be done.  An I&amp;T type manual assumes you know much of the basics to start with and has many gaps in the details. 

When you get down to it, you're not going to be able to do 100% of it, unless you have a way of grinding a crank, valves, etc. Some things just have to be done in a properly equipped machine shop.

And if you have any troubles or questions, we'll be glad to help you out here.