Quick update: So the top cylinder studs were completely gunked up with some sort of silicone rubber stuff. That might explain why the heads were shot a year after they were rebuilt by the PO. At least now I know that he didn't lie about the top end being completely redone a little over two years ago Cylinders and pistons are in great shape, cam followers are brand new and the con rod also feels perfect. Still put the siebenrock power kit on regardless, I'll be selling the old jugs. Took a few hours, but it all went pretty well. No real problems along the way , but why in the name of all that is holy has Siebenrock gone with the older style gudgeon pin circlip is beyond me. Pain in the fucking ass to get those in. Tomorrow I'll fire it up for the first time in 5 months!