1972 gmc 402

[hamjet]

I thought all bbc heads had screw in studs, may be wrong. Has the cam been changed, too high lift they could be touching the pistons, bending the push rods. a motor with high mileage with heavy valve springs could have worn the rockers or broken rockers causing them to lean sideways which will bend the push rods. once they lean like that the rockers cut into the studs, time to check them all out...