Bearing Service Company
1040 NW Everett St.
Portland, OR 97209
(503) 222-1366

This is the machine shop that MBI Motors contracts their head work out to. I took the head from my 300E there for a full R&R a couple months ago, and it's worked flawlessly since I put the motor back together. Their services are a bit pricey, but I think you get what you pay for.