The guides were machined correctly for the seals and we added the correct springs, keepers and retainers. Other than freshening up the heads over the years, the seals have done their job @pittsburghracer can probably put his suggestion.
Just looking at the pictures im
Not going to add my 2 cents on stock heads. Just to many variables that need checked and addressed before using that seal. I will say it’s important to use the right tool and I soak mine in oil before installation.