Damn good info

Jadaharabi said
Back to the Magnum engines. I now have several 5.9 running engines in various vechicals. A couple of weeks ago I bought another complete 2000 ram 1500 4x4 for $500. Have not decided to part it or drive it yet. I have bought trucks and Durango with the 5.9s for $100 to $1200. You can get the rusty rams with a bad transmission for $350 to $600 al day long and the one with a bad motor are even cheaper.

So far none of the magnum heads I have removed have been cracked. So is the cracked heads a problem with engines that have overheated more so than anything else?

The plenum gasket leak has contributed. Imo Sucks oil, it cooks..glows, pre ignites.
Only real bad plenum leaks will get it rattling though, others just eat oil and gas and crust up the chambers.
The other thing about magnums... unlike La heads, mainly the 360 in my experience and not too many 3/18, which the in studs break when you try to remove the nuts... with a magnum the end studs are known to just break from the manifolds expanding and Contracting over many years. It's actually pretty common with foreign cars aluminum heads and cast iron manifolds as well. Once that happens ..it leaks and you can end up with a burnt valve, seat , and cracks can follow. My truck since in my possession has never been overheated. Don't have a any indicator it ever was. Doesnt mean it hasnt been. Cylinders still had cross hatch @299k. I'm really happy you had good luck with them Magnums Randall... I used to have really good luck with 360 heads...every one I ever found was good ....and then one day I pull a pair with confidence and find out they're cracked not at the seats but near the exhaust ports on the outside of the heads...then the next 3 sets were hit and miss, one would be cracked. Hope this last set I pulled yesterday are good!