blueprinting small block oil pump

Agreed with the above, probably about all you can do. An oil pump is a fairly simple device, there really isn't a whole lot you can do to them. As stated above, FSM will have nominal clearances to verify against, making them consistent across all surfaces is the goal but easier said than done. Measuring for pump cavity concentricity, consistent depth and flatness of the cover may be worthwhile exercises.

If you only have one unit it may be wiser to leave it as-is, once you start messing with machined surfaces there's no turning back. Swapping components from other units may reveal better tolerances between parts but obviously you'd need to have more than one pump on hand to compare against.

There is a company called Precision Pumps that offers this service, I bought a SB pump from them a while back. They enlarge and smooth the cast passages, inspect/correct rotor/cavity/cover clearances and coat the internal parts with teflon. Expensive proposition, not sure if it was worth the cost.

Incidentally I ended up trashing the pump body during the install. One of the main studs was a hair too long and when I went to torque the pump down I didn't see it was cocked. It split right in half! I got another non-blueprinted pump and swapped in the teflon coated rotor and cover. I looked at how they smoothed the passages out on the cracked body and copied it. Worked out OK, no problems.