i just use universal dorman soft plugs. 8 bucks for 10 rather than 45 bucks for 6. they were ordered for a toyota 22r, and i only needed one, so i wasnt gonna pay 45 bucks for one soft plug. bought ten, used one, threw them in the parts cabinet. then i used a couple more blocking holes in my ABA block. i love buying parts for one thing, then getting to use them on something completely different.
as for installing, just smear some silicone on the back edge of it that seals to the block, then take a socket that is slightly smaller than the plug, so the plug will just fit over it. and tap the plugs in with a hammer and that socket. its WAY easy. and if you have plugs in the block right now, take a punch, and punch it right at the edge, and it should turn sideways so you can grab it with pliers and pull it out.