I will attempt to answer your question.. All the machine work is done that rules allow.. We either allow you to choose cams or we can suggest what we'd use per your application... The 2 most complicated parts of these engines is the cylinder head and carburetor.. Most people buying such a kit likely has no means to properly machine the parts as well as know what the make up of a good carb combination they'd need.. In this case we also assemble these 2 parts so you don't have to guess on them..
BUT even though all the proper work / machining has been done its tough to pass on the theory of making HP... Only time,, patients and lots of testing will move you toward a true professional built engine.. As mentioned though, if you buy a kit from us and you come to a crossroads or uncertainty (sp) we are just a call or email away and WE WILL walk you through it...
For the ones that are uncertain of their skills,, we have a DVD that takes you from start to finish..
Hope this helps
JD