I am looking to buy a 426 style hemi water block to build a motor for FAST class racing. I have been doing some reading on various castings. From what I can gather, it looks like finding a new block that was cast just prior to them discontinuing the original style blocks and going to the new World block is the way to go.

I have read some about core shift in earlier "new" hemi castings. Which castings are the ones to stay away from? How can a person tell by looking at the block?

I have found some with MOPAR cast into the side of the block and others without. What is the significance of the castings with MOPAR cast into them?