The #53 blocks are famous for cracking if used for pulling heavy loads, especially here on the hilly east coast. If you search the site, there's an older thread devoted to the 53 block. It was cast between 98.5 to 2002. There was actually a kind of non-advertised replacement policy/ recall of 5years or 105,000 miles where Dodge would replace the block or entire engine.

I'm putting a "90" 12 valve into a "02" If I get the harmonic balancer from a mid 90s truck with the sensor will the tach and cruise work like they are designed to?

I'm interested in this as well, friend of mine has a 24V with some problems, I can get a cheap 12V to replace it. I would just like to get all my ducks in a row and figure out potential problems first.