If you intend to replace the piston on your 42 Special, with a 242 piston, I can tell you that it did not work for me. I acquired a 42 Special that appeared to have been straight gassed. Piston and cylinder were scored, but I was able to clean up the cylinder with acid. Except for Husqvarna OEM, I was never able to find a 42 Special piston, so I purchased a Meteor piston that was spec'd for a 242. Once installed, I was never able to get adequate compression. End gap on ring was way over. I did not have the tools to measure the cylinder, or piston so I can't really tell you if the cylinder was beyond salvaging, or the replacement piston was under size. I was never able to find a used cylinder/piston. If you want to spend the money, Husqvarna, still has OEM parts, and Tecomec has a 242 piston/cylinder kit. I eventually sold the saw for parts.
