I always use the deep steel plugs and JB weld never had an issue ever--I feel like the steel fits tighter for sure--it is also very important to check each hole and smooth out those digs and gouges made when removing old ones--I use the tootsie roll and then even JB the streak or gouge--then plenty of JB weld---I also have a driver made from diesel wrist pin that fits the 1 5/8ths units perfect so not to distort--I ALWAYS use the deeper ones figuring they have more sealing surface and will not distort--brass is a fad from the past--They are too soft these days cheaper alloy I bet. And..I agree that a dose of stopleak is smart no matter what you are working on--