Originally Posted by rivvgs
so I have been told, I have read and been told by my machinist. that the 4 bolt blocks of the 2 piece main seal era where the largest portion of 4 bolt block originate. often have more core shift issues.when over boring a cyl core shift can greatly effect the thickness that is safe to bore. I am not sure why but the latter blocks tend to have less issues
Casting techniques have changed a lot. Cores are formed around hard foam patterns that are not removed prior to the pour so there isn't a disturbance of the core for pattern removal anymore. Castings are done with higher head pressures which improves distribution, lessens pits and holes, increases density. The process is highly automated which is more consistent than humans doing this hot and dangerous work. My maternal grandfather worked as a overhead crane operator at Jones and Laughlin, as a young man he got me in for a tour, that and me working in a slaughter house, packing, mechanic, truck driver and candy making companies over my summers and holidays really raised my GPA in school. Which brings me to taxpayers covering college tuition; sitting around with my buddies the subject of what did you do on class breaks came up; "anybody go to Cancun?". The answer was everybody either caught up on studies and/or worked to make money. So when I see hordes of vacationing students on TV, I'm not too inclined to pour more tax dollars into free college for these folks because they borrowed their way through school. Trading your time for debt is a life lesson the young need to learn.