[Walt Fricke]

Patrick - they won't. The sleeves are a close fit, but not a tight one. They have a sort of flat cross section O ring around them, as you will see when you knock them out. You will want to replace that just because you have new sleeves. But the sleeves will still be loose.

And that does not matter. As long as the stakes hold the sleeves in place against the force of the injection trying to push them up (and I don't think it is much of a force), and both O rings (inner plus the fat round cross section one which holds the injector into the sleeve) seal out the atmospheric pressure air in your engine bay, all is good.

The test (too late for that now) of this assembly is to spray some starter fluid or carb cleaner with the engine at idle around the hole in the runner where the sleeve can be seen. If the seals are bad, some of this stuff will be sucked into the runner, and the engine's speed/note will change.

Me, if I can pull out my injectors without also pulling out the sleeve with it, I leave them alone. But if you like replacing things, go ahead. But it is always a good idea to have some new sleeves on hand in case one does come out - yes, they get brittle.