I think they came pre-cracked from the factory.

 

I cleaned the heads up and for ****s and giggles had them magnafluxed. No cracks anywhere!

 

That's absolutely amazing.

 

I have a 5.9 as well and have kicked around this idea also, but, everything ive read and heard about the stock heads is not good, there so prone to cracking i wouldnt trust them down the road, even if there ok now.
Im thinking about buying the EQ heads as bare castings (much cheaper) then have them assembled down the road as more funds become available, this way i can do my own gasket matcing and bowl cleanup as well, while there bare castings...

 

You leave those off the truck and mount them over your fireplace like the trophy they are. In all seriousness if they are fine you could get away with a little porting and milling. I looked up flow charts and they are on par with chevy vortec heads which every chevy guy thinks are the best iron head ever concieved, maybe divine intervention even. Until you mention hemi or ls heads that is Sorry off topic. If it wasn't for the cracking the heads aren't terrible. Its the intake manifold that really kills flow from the it seems experimenting I have done.

 

If I wanted to make decent power out of this engine I would throw in a strong cam, some EQ heads and a good tune. I'm really just building a cruiser that will weigh about half or even less then the truck the engine came out of. Coupled with a set of 4.56 gears and a 31" rear tire I'm confident this there will be plenty of pickup for my needs. If I had the spare $$$ in my budget I would spring for the said upgrades but it's just not there. The heads are not cracked and the engine ran good before being pulled so it'll run good again.

 

In that case, don't cut the decks unless you NEED to. A bit of porting/gasket matching certainly won't hurt you.

 

I just checked to make sure the decks were flat, which they are and went through each port and smoothed them out a little bit.

 

I would look at head gaskets from Mr. Gasket. I'm using the 5805G steel-core graphite gasket for my build. It's .038" compressed, while the stock Fel-Pro is I think .055" (someone correct me if I'm wrong). The bore diameter is 4.140" while the stocker is 4.180". So both those will increase your compression a little. I think they even make a gasket that's .032 compressed thickness. And about the same price as the Fel-Pro.

The composite/rubberized gaskets act as insulators. An added bonus of the steel/graphite construction is these gaskets transmit heat so fast you'd think they were pure copper. I think that's probably a very good thing with regard to heat being actively transferred from the heads to the block through the gasket and not solely via the cooling system.