Welcome to SCJB

Gonna need a little more information about what you want to do. If you're looking for a basic overhaul with marine tolerances you can go to just about any machine shop get it done. If you want a good high performance build that's another story.
Also, how much of the build are you able to do yourself? Do you want someone to do the machine work and you do the assembly, or do you need a place you can drop it off and pick it up when ready to install?