Remind me about the "53" block

[odinjunior]

Looking through C/L at 5.9's and one ad said "not a 53 block". I remember back when I had my '98.5, that it was something I didn't want but I can't remember why or how to tell if a truck has it.
Someone help me out?

 

[gsbrockman]

Some 53 blocks had cracking issues. The casting number "53" can be found on the side of the block near the injection pump.

 

[odinjunior]

Found it... Should have searched the web first..

http://www.stamey.info/truck/cummins53blockfaq.htm