Was thinking on rocker shaft some of those are right hand and some are left hand, cylinders 2,4,6,are left hand angle, not interchangable.
not sure how far off from center on valve or push rod if assembled wrong. check rocker arm shaft for bend in it. binding, could be valve seem free but at certin point binds enough to break rocker. could be you got 11 hydralic lifters and one mechanical. I think what I would do is repair the broken lifter, assemble rocker shaft and adjust rocker arms as if they were mechanical lifters, .06 intake .13 exhaust. if they make noise adjust for hydralic. Maybe the car engine was a truck engine in a car.hope this helps
jbennett
40 burb
