Lets talk about "freeze" plugs...

If you install the Mopar style thick, shallow plug to just beyond the bore chamfer (about 3/32), you get the ledge effect I mentioned.

If you install the gm style that way, the plug protrudes into the water jacket, eliminating the ledge.

The depth also helps true up the plug inside the bore.

gm style dorman part # is 565-030 (or 565-031)


I've never used any sealant, and never had any leaks that lasted more than one (rare) or two (very rare) heat cycles.