340 with metal in oil pan

We had a set here with the bottoms of the keepers broke off on some of them. With the valves hitting the pistons like that the bounce probably put some stress on them over time. Years ago that was a trick they would do on 318's and 72-73 340's and 360's. I guess the builder here must have read that article and didn't take into thought of the 68-71 340 only having two valve reliefs per piston. **** happens. LOL

You can see in the pictures after looking close they are the bottoms.