I think the 351 is in my future but I really don't want to install in myself.
What questions would you ask a mechanic to qualify his ability to do it right the first time?

 

Find a shop that deals with MX Bikes, the high horsepower singles need frequent rebuilds

 

Any good bike shop should be able to do it.

 

 

I love it. Stay away from people who have the special tools that may be needed, the diagnostic equipment that might be needed, and skills to do the work... golden.

OP, if you want work done, find out what shop, dealer or independent, that has the reputation for good work. Ask riders. You will learn. Where I worked, we had a good reputation for good work and fair prices. Others didn't, especially some of the heavy discount dealers. They cut corners somewhere. Ask races, whether they do their own work or not, they may know who is best. You may pay more per hour, but you may be getting what you pay for.

Again, reputable shop.

 

Another option is to link up with a forum member nearby who has successfully done the mod, ply him/her with beer, and learn how it is done.