I would highly recommend getting yourself some new OEM valve stem seals. Personally, I wouldn't even consider putting a fragile/crucial item like that through such abuse and trust it to work properly. Installed, used, removed and reinstalled. Not only are they famous for getting damaged during installation/removal, but they're a major bitch to change. That's something I'd like to do 200% right while I've got the engine ripped apart. Just my .02.