I did a full top overhaul at 350hours on Gen 2 3300 because of low leak down, a pass but low, it had stuck rings, I'm very glad I did it, I also converted to hollow push rods, it cost just as much to convert to hollow push rods as the top overhaul kit so I spent twice as much as I could have and spent more than required as it only needed a set of rings, I believe the engine was overheated long before I owned it, the engine now has new valves, double valve springs, hard valve washers, hollow push rods and rockers, high leak down lifters, valve relief pistons, new rubber dampened through bolts, new flywheel bolts with star washers and all the rest of the top overhaul stuff !
So there are definite improvents made and the engine now gives me some peace of mind as to its reliability, the hollow push rods was probably overkill but I still wanted it ! The engine has done twenty hours and does not burn or use oil and runs fine. Most of the new parts are a big improvement including valves and pistons, my opinion and experience, just sharing and giving my two bobs worth !