My machine shop has told me that the 5.9 Magnum heads off my motor are cracked. I need to pickup some replacement heads. I understand that junkyard Magnum 5.9 heads are prone to the same issue, as it seems that the castings are poor on these heads.

So, I'm in need of some replacement heads. I want heads that are a total bolt-on replacement. I thought about Edelbrock heads, but they require new rocker arms, studs and pushrods. In addition, I'm not doing any upgrades to the short block, so what are my possible options for replacing my existing magnum heads with something that is not crack-prone?

The consesus will be Carolina machine and Hughes engines. New iron heads based on the OEM head design but better quality and better function.

Two good options are:
RHS/Indy
EQ "Iron Ram"

Both can be had at Hughes assembled as "factory replacement" but with better springs.
If you want to go with upgraded components/more prep, then Hughes has that too, but IMM (board member OU812) has package for valve job, prep, upgraded components that's a good deal.
As I'm sure other businesses here have...

Good luck,
Ran

Is an iron head my only choice? Anyone make a budget aluminum Magnum head?

No one else offers a decent aluminum Magnum style head?

best bet for the money:

http://www.hughesengines.com/Index/produ...mp;partid=25701

new EQ heads, can resuse stock valve gear, has upgraded springs and new OEM valves...

while you're at it I'd send them your roller cam and pick up one of their regrinds, probably the HER0814AL if it's in a workaday truck....

nevermind...I misread the post I quoted! I read "does anyone make an aluminum magnum head" not "does anyone ELSE make an aluminum magnum head"


to my knowledge, edelbrock is your only aluminum head source for a decent street head.

all others are iron.

Wasnt pro comp making an aluminum smallblock head? What's the status of that?

I thought someone had these in hand and was supposed to come back with data? I know I read it HERE.

Another thing that needs to be addressed is, If he will be running the factory pistons, Going with Aluminum heads the compression should be raised a good full point to compensate, so theres another exspence unless he mills the Aluminum heads. IMO it isn't worth it, The RHSs flow just as good or very close as the Eddys OOTB between the both.

I agree with Patrick.
I got on a kick about 3 years ago
and became curious about:

"How much extra heat leaks away from a cylinder head made of aluminum,
versus one made of cast iron"

I posted a question here on Moparts titled
"Efficiency of aluminum vs iron heads"
which eventually grew to 30 to 40 replies and posts,
with many external links,
including this one:

http://www.carcraft.com/techarticles/ccrp_0602_iron_versus_aluminum_cylinder_heads_test/index.html

After further research
including reading the heat transfer sections of several college engine textbooks,
the conclusion was:

"There is no efficiency
or power disadvantage
to aluminum heads,
and there may be a 2 to 3% advantage"

Why is this
since 'everbody knows'
aluminum has a higher thermal conductivity (K)
than cast iron?

The highly technical reason is:

"The rate of Heat Transfer from the combustion gases to the metal walls is dependent on a series of steps,
like links in a chain,
and the 'weakest link'
is at the 'boundary layer'
where hot gas touches cooler metal.
Since the boundary layer is about the same in both types of cylinder heads,
the 'real world' heat transfer is also about the same.

Richard Stone's book has a graph showing Japanese research on aluminum versus cast iron cylinder heads:

http://www.amazon.com/Introduction-Inter...7025&sr=1-4

Are there any NOS remnants of this older
P5153847 MP aluminum cylinder head?

http://www.moparsupercenter.com/mopar-pe...47p5153847.html

360view,
Thanks for that excellent info. It seems everyone has a "rule" for aluminum heads from "you must raise compression" or they "drop compression".
In the end, when I bought the Edelbrocks for my 408 stroker I came to the conslusion that compression ratio stays the same (built mine for 10:1 nice and safe on pump gas) but you can run a higher compression ratio before you start to see negative effects with the aluminum heads.

Scott

Thanks for all of the info and replies. Was hoping that the Magnum 5.9 head options might be widening, especially for aluminum head options like what is being done for the big blocks - for example:

http://store.440source.com/Stealth-Aluminum-Cylinder-Head-COMPLETE-SINGLE-HEAD/productinfo/200-1055/