I have a couple jonsered 630's that I think I want to get one of them up and going. I want to keep it jonsered and not convert it to a husqvarna 272/269/266. I know that these says are the twin thin ring piston. If the cylinders are any good what's the replacement piston for that saw? Also and any other tips on bringing one of these back to life? I'd like to get this saw working nice. I plan to build a custom muffler and possibly remover the base gasket but wanted to ask how well these saws react to more compression and less timing. Any recommendations?