Easy to clean out the bore IF... They are not filled with carbon. Just make very sure you get the old copper gaskets out. You do NOT want two gaskets in the bore. A 12 gauge cleaning brush works well. Make sure you clean off the top of the engine around the injectors too. Crank the engine over a few times with no injectors in to blow out any crap. The torque is 35 ft lbs.Please use anti sieze on the injector body threads ONLY. You really do not want it on the copper gasket. Use a straight dental pic to "feel" the cast iron seat in the head for compression cuts. You place the point on the seat and move it around the seat. It there is a cut it drops in and stops like hitting a wall.