How can the disk type be installed in the core plug holes? Seems as soon as u try to pound the center down to seat it, it will drive it into the block. The only place Ive ever seen the disk type is at the end of the camshaft.
Another way to get the old ones out is to drill a hole in them, maybe 1/2", insert the pointy end of a rolling head punch, then pry them out. Might be the answer in a situation where access is too tight to pound them.