Brass plugs are available for the side holes in the block, but I haven't been able to locate any the right size for the big plugs on both ends of a stovebolt block. With a little creative metal whittling, a flat brass sheet about 3/32" thick can be formed into a convex plug to fit those holes.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!