I decided to try and tackle valve seals tonight. I've never done this myself before and my brother gave me all the tools I needed. I've had some exhaust smoking and the head was done about 20 yrs ago. Please let me know if anything below relates to the smoking and anything else you can advise on. --I put air to #1 cylinder and get a moderate leak out of cyl #3. Plugging the spark plug hole stops that leak. -- Still air passing through somewhere. Definitely not oil filler tube, other plug holes or radiator. Sounds like coming right from #1 cyl somewhere. I should've put my stethoscope on the exhaust manifold. Maybe it's passing by the exhaust valve and I'm hearing some of it through #3 cyl plug hole. Does that make sense? No air leaking at #2 spark plug hole though. --Capping the carb has no effect on this additional air leak. No fuel coming out of carb anywhere with air on Cyl #1. --Took spring off #1 cyl and the o-ring seal was where it should be and did not appear distorted or cracked. It was still flexible. --Putting it back together is more difficult. I've got the same style o-ring seals that came out (Fel-Pro #407). Dropped spring into place and the retainer. Then, placed seal over valve and got it to lay in the retainer. The shoulder inside the retainer is not very pronounced. If the spring shifts much while compressing it the o-ring can drop down off the shoulder and get cocked on the valve stem. --Are the Sealed Power design seals easier to work with? Thanks.