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Originally posted by Fostang:
I prefer aluminum heads for the above mentioned facts plus the very same thing that makes iron heads produce more HP*, that aluminum heads help resist detonation because they dissapate heat faster.

*only if the heads are equal.

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Is'nt it true You can run more compression with aluminum head's? Or a little More boost? Makes a difference with this shitty 91 octane We feed our car's in california.
 

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Posted by 92stangLX (Member # 3252) on :
 
I think that paying a bunch of money to have the stock E7 heads is a waste. The GT40, GT40P, or World Products (?) iron heads might be another story.
 

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Posted by svt306snake (Member # 1967) on :
 
compression is an very big factor in picking iron or al heads i have both and they are different to each application
 

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Posted by Apexmotorsports (Member # 5307) on :
 
The reason why some people port stock heads is the racing series they are in restricts them to do so. Iron heads are good if they have port work done to them. Thumper Performance in Florida swears that his ported stock heads can get you to about 300RWHP with the right combination. Mike from Thumper is a real cool guy and he can be reached at http://www.thumperoforangepark.com/ If you call him tell him Mike Mak from Apex Motorsports/ Drive Magazine refered you.

FWIW, for our $6500 project car I will be porting a set of stock heads to see what kind of performance I can get out of it, It's going to be very interesting to see the results because I have NEVER ported a set of heads before BUT will be getting some help/ tips from some of the best porters in the country.
 

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Posted by Fostang (Member # 3752) on :
 
Thumper is definatly a cool dude.
 

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Posted by JoeT (Member # 298) on :
 
I always thought it was the other way around, apples:apples 2 heads that flow the same the iron will make more power through greater thermal efficiency (less heat lost to the environment).

OTOH, AL heads allow you to increase compression a hair, which possibly mitigates or even is more important then the lesser adiabatic efficiency.

One concern is if the block is iron and the heads alum, certain head gasket issues are more likely to occur than if the heads were iron with an iron block due to differing thermal expansion rates.

Also, I'm not a metallurgist and as far as welding goes I'm barely competent enough to get two bolts to stick to each other , however, iron has got to be easier to repair than AL due to how much easier the metal is to weld on, and just how notoriously difficult it is to work with aluminum as far as structurally.

Now as far as the casting process goes, since alum is so much more malleable than iron, I'm sure the costs to manufacture a certain shape especially if cutting is involved are lower with alum, and we all probably know just how much easier it would be to mill/etc. an aluminum part vs. an iron one.

still apples: apples I'd rather have an iron head that flows the same vs. an alum. head for some of the reasons I stated.
 

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Posted by FasterDamnit (Member # 442) on :
 
Joe,
Cast iron repair is much harder than Al. Best process is probably Gas Fusion Welding.
 

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Posted by JoeT (Member # 298) on :
 
really? I thought most repairs would be a semi-trivial (like for a crack) weld-a-slag and grind on it. but wtf do I know, heh anything outside of JB weld I don't know anything about
 

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Posted by FasterDamnit (Member # 442) on :
 

quote:

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Originally posted by JoeT:
really? I thought most repairs would be a semi-trivial (like for a crack) weld-a-slag and grind on it. but wtf do I know, heh anything outside of JB weld I don't know anything about

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JB Weld

Yeah, I tossed a nicely ported 289 head when I was quoted up to $300 to fix a crack in the deck. Wish I had known that before all the grinding...
 

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