Question on shimming and porting ls6 oil pump.
Just pull the front cover off the pump and pull the two gears. You'll see the casting flash in the main oil track at both the entry and exit ports. Your goal is to smooth the passage/transitions, that's it. For shimming, remove the relief valve cap, pull out the spring, measure its OD, and that's the OD of the shim you'll need. I probably wouldn't shim it more than .125". You can purchase shim stock from one of the many hardware stores around, or from www.McMaster-Carr.com.
