OK, I know we like to keep it in house, so to speak, but;
Source for very comprehensive rebuild book.
http://www.sohc4shop.com/catalog/index.phpHead work, maybe pricier than some, be second to none.
JMR Porting email should still be jmrieck1@comcast.net Phone# (508) 479-9627
The book is by an extremely knowledgeable person, especially with the earlier sohc bikes, and since not much was changed, this book should still give a wealth of info. The price is rather high, until you compare it to a set of intake manifolds!
Mike at JMR is probably considered in the top 5 of head porters for the 750. You might find the porting service cheaper elsewhere, but it isn't likely to be better. And he does different stages of porting, from a mild cleanup of casting marks and such, to very open ports. His CB puts out around 100 hp, rear wheel, last I knew.
The ride IS the adventure. The destination is just to get gas!