Valve seals tore on break in
This is a BB 452 head.
The guide on the right is how the intakes are on these heads.
The one on the left is how both are on most castings.
When I’m cutting the guide bosses for seals/retainer clearance on 452’s I start out by removing the big base and making it like the exhaust.
Then cutting the OD of the upper part down to facilitate the use of a smaller OD seal, and shortening the height at the same time.
This is a BB 452 head.
The guide on the right is how the intakes are on these heads.
The one on the left is how both are on most castings.
When I’m cutting the guide bosses for seals/retainer clearance on 452’s I start out by removing the big base and making it like the exhaust.
Then cutting the OD of the upper part down to facilitate the use of a smaller OD seal, and shortening the height at the same time.