While doing transmission fluid / filter change I was able to ID my new to me 99 as a 53 block. Not very excited to see that, as I was hoping that while it was made in Mexico it could have possibly skipped that block. Is there more than one "type" of 53 blocks or just one and they are inferior casting? The truck has 164K on it at this point and engine runs well, no blow by. Been reading the forums on thr 53 block and wondering if there are others that are going without an issue and if there are more than one type of 53 blocks?