I'm looking for a diesel repair shop on/near the I5 corridor in WA state between Burlington and Chehalis who can change the timing for me on a older mechanical Cummins 8.3 (1994) in a motorhome.

The Cummins shop in Renton say they do NO mods to include non factory timing specs. My CPL is 1406 with factory timing of 12 degrees. I want to try 15 degrees. I have number 10 fuel plate, star wheel turned up, higher flow exhaust.

Any leads on a shop with room for a 38 foot motorhome who will reset the timing would be greatly appreciated.

Dan - currently near LaConner WA