I have pulled many sets of injectors from cars in the yards. I have only found one set of injectors that were in good enough condition that I did not even want to open them up for cleaning. I sold the set to a forum member a while ago. For the cost of the injectors, shipping them to be reset, the labor, the cost of shims/springs, etc; it would be better better invested in a set of fresh nozzles and there are several people on this site who charge a reasonable rate for a rebuild. Myself and Greazer being two of the people.

You probably need new injector nozzles if you are certain they have never been rebuilt in the 300K miles. A pop test is the only way to be certain, though.

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

That is a really good deal.

__________________
84 300D, 82 Volvo 244Gl Diesel