[ItBites]

I have run the sleeves you describe in my 427 BBC that is being replaced right now for other reasons.

The reason I installed them was to correct the lifter bore alignment errors intrinsic in factory block machining. It allowed me to square the lifter to the cam as well as locate the bores correctly for proper indexing. I felt this accuracy improvement was needed in order to run the high RPMs I needed from the "little" 427 motor (shift point was 7400 RPM).

The sleeves are pressed and require the overbore to correctly compliment the sleeve OD. There should be no disadvantage in life. If your oiling system is working correctly, there should be only minor (not detectible) reduction in friction. They can be more forgiving if you get a piece of trash in the bore.

Whether they are an advantage to you is more likely a function of your engine's intended operating regime associated with the requirement for correct valvetrain geometry - unless FEs have inherent oiling problems in the lifter area, then the sleeves may reduce the tendency to gall during operation. Someone else can speak to any specific FE issues.

That is all.