I own a '77 C-27 that I am currently refitting. I have obtained tons of useful info from the catalina owners web site (www.catalinaowners.com)
. There is quite a bit of info there regarding the keel bolts. Additionally, Catalina Direct has keel bolt replacement kits for this very job (www.catalinadirect.com)
. If nothing else, you can call Catalina. I have found them to be very helpful with just about any question I've posed. They have some of the best customer support I've experienced in todays world.