This is from the E-Book on the old site,
“3.3 - Dorman Freeze Plug Replacement ( Paul Saltwick, May 6, 2004 )
The part number is DC-11, 1.75” expanding copper core plug.
Yes, Dorman has a website that lists distributors.
NAPA is one that sells over the Internet.
The plug should be a snug fit in the block and not driven in.
They can be turned down with a driven socket against Emory paper.
If you need to do this for a blown out plug, make another the same
dimension as a spare.
I use epoxy sealant on the edge.
You only turn the nut 2 turns. Directions are on the bag, however
they are often sold in bulk.
You may need to grind down the acorn nut crown on the rear plug
to clear the throttle linkage.
Installed correctly they will hold a 7 psi radiator cap.
Joel adds on Jan. 25th, 2005:
NAPA has them, part #600-4029. Cost is around $4. You can also
buy them off NAPA’s website: www.napa.com."
I’ve used Dorman freeze plugs [ not on a Jag] and a lot easier to get into a tight place with the engine in place.