Dorman freeze plug

[86 1/2 Brutus]

7 or 8 years ago, we blew a freeze plug on the cylinder head and replaced it with a Dorman rubber one.  It blew out the other day.  We were just going o replace it with another rubber one.  ( we plan on pulling the engine in a few months and replace all the freeze plugs, gakets, seals, timing chain etc.  On doing an internet search, I see Dorman also makes a copper one that you can put in with a wrench.  I've only seen one mention of this in another forum where the guy says they work so well that he replaced all of his with these.  I cant find any other info on them.  Does anybody have any clue?

[85lebaront2]

I have used them before, I believe on a 390 FE engine, They have a slightly coned inner dish that when the nut is tightened flattens to spread and secure the copper portion.

[86 1/2 Brutus]

makes sense

[86 1/2 Brutus]

do you have to bang them with a hammer to start them or just start turning the wrench?

[85lebaront2]

I think it tapped in, but not super tightly, then I held the hex on the plug body and tightened the acorn nut. BTW, you haven't lived until you've had a rubber one blow out of a 390 and dump all the coolant on the shop floor.

[FordFETruck]

Bill, there have been people that have put 1 3/4" steel and brass core plugs in FE engines and had those blow out as well because they actually take 1 49/64" diameter plugs and most of the kits come with 1 3/4". Can't imagine the shower that would give especially when hot!