Cast Iron vs Aluminum Cylinder Heads - Chevelle Tech

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post #1 of 23 (permalink) Old Jan 12th, 11, 5:16 PM Thread Starter
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Cast Iron vs Aluminum Cylinder Heads

I have my 427 SB out of my car due to a leaky head gasket or cracked head who knows yet?
I know a cast iron head if everything is equal makes a bit more power than an aluminum head.
But an aluminum head is more repairable over a cast iron if something breaks or detontation etc.
But whats more reliable for leaks?

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post #2 of 23 (permalink) Old Jan 12th, 11, 5:20 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

a good head gasket

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post #3 of 23 (permalink) Old Jan 12th, 11, 5:34 PM Thread Starter
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Re: Cast Iron vs Aluminum Cylinder Heads

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Originally Posted by big_orange View Post
a good head gasket
True , I thought I had one

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post #4 of 23 (permalink) Old Jan 12th, 11, 7:13 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

Dave, just had the Dart heads freshened up. Deck surfaces were cut to just about a mirror, block is at the machine shop getting finished, I did see it after it was decked, same deal. Plan to use MLS head gaskets. Another worthwhile investment (in my opinion) is a head stud kit. I'd stay with your plan of just fixing what you have and make needed improvements along the way.
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post #5 of 23 (permalink) Old Jan 12th, 11, 7:42 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

I have always used Permatex Hi Tack spray. Been using it since 1970 with up to 11:5 compression and steel shim gaskets. Like the others said, quality machine work. I did drop a valve once and scraped out a very nice 049.
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post #6 of 23 (permalink) Old Jan 12th, 11, 9:10 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

I prefer alum because it is lighter and i can get away with higher compression on the same gas. And in alot of cases easier to repair. Im sure iron has some advantage (like price) but not enough for me.
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post #7 of 23 (permalink) Old Jan 12th, 11, 9:37 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

I personally like an aluminum head i had to wait a lil longer to get the set i wanted but really worth it i bought a set of 210 Pro-filers from Chad speiers love um i threw them on the scale before i buttoned up the block and the steel head weighted 48 lbs. the aluminum 25 lbs. basicly two heads the weight of a steel one, around 50 lbs is alot of weight to save aswell.
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post #8 of 23 (permalink) Old Jan 12th, 11, 11:48 PM Thread Starter
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Re: Cast Iron vs Aluminum Cylinder Heads

Well I will find out what happened to this thing and decide from there.
If they aren't damaged its the smart way to go and re-use them. then add my new solid roller.

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post #9 of 23 (permalink) Old Jan 13th, 11, 1:07 AM
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Re: Cast Iron vs Aluminum Cylinder Heads

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Originally Posted by Dave427 View Post
Well I will find out what happened to this thing and decide from there.
If they aren't damaged its the smart way to go and re-use them. then add my new solid roller.

Dave
Good plan
As far as a power difference in theory the cast head might make more but this just hasn't been shown to be true in the real world
It has been tested by one of the magazines a few years ago & it was a pretty decent test as I recall with "like heads"
The Aluminum ones actually made slightly more power

I do have one test we did a while back
It was the Dart iron Platinum vs the Dart aluminum which are supposed to be the same or very close to it
We took a set of Platinum 215cc Iron heads off a circle track deal & stuck the Dart 215cc aluminum heads on with no other changes
The power was too close to call & this is without bumping the compression which means the aluminum head probably would have been the winner if things went as they are "supposed" to
If memory serves the torque was slightly better with the iron head but the peak power was higher with the aluminum but again it was within testing error for me

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post #10 of 23 (permalink) Old Jan 13th, 11, 1:14 AM
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Re: Cast Iron vs Aluminum Cylinder Heads

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I know a cast iron head if everything is equal makes a bit more power than an aluminum head.
Not that I am aware of. But besides that, if you choose aftermarket aluminum heads, you have a plethora of options available to you, and with those options comes more power. I believe that there are a number of aftermarket aluminum heads that flow better and make more power right out of the box than some ported iron heads do.

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post #11 of 23 (permalink) Old Jan 13th, 11, 10:30 AM
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Re: Cast Iron vs Aluminum Cylinder Heads

The theory was that iron heads would hold more heat in the chamber, while the aluminum heads would shed that heat into the cooling system more readily than the iron.

That all makes sense, but all the new chamber research shows up in aluminum heads first nowadays, so a more efficient chamber in an aluminum head more than makes up for any potential heat loss over an iron head with a lesser chamber design.

Personally, I'm a huge fan of internal engine coatings. I get the best aluminum heads I can, and then coat the chambers, valves, ports, and piston tops with ceramic engine coatings. This insulates the chambers/ports and keeps more of the heat in the chamber.

Because of the coatings and the weight savings, not to mention the ease of repairs, I'll never run an iron head again. It's like the roller cam thing- yes, they're more expensive, but I'll never run a flat tappet again either. Too many advantages to rollers...and aluminum heads, for that matter.

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post #12 of 23 (permalink) Old Jan 13th, 11, 11:27 AM
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Re: Cast Iron vs Aluminum Cylinder Heads

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Originally Posted by Scotch View Post

Personally, I'm a huge fan of internal engine coatings. I get the best aluminum heads I can, and then coat the chambers, valves, ports, and piston tops with ceramic engine coatings. This insulates the chambers/ports and keeps more of the heat in the chamber.
Hey Scott, could you elaborate on the ceramic coating? Is this something a backyard wrencher can do? Or do you need to bring it to a machine shop? Thanks.
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post #13 of 23 (permalink) Old Jan 13th, 11, 1:24 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

Some companies such as Tech Line sell coatings for the do-it-yourselfers, although I don't know if that would work as well as coatings that you can get professionally applied. Anyways the internal engine coatings are supposed to keep engine parts cooler and "reflect" the heat. Kind of like ceramic coatings on exhaust headers.

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post #14 of 23 (permalink) Old Jan 13th, 11, 1:38 PM
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Re: Cast Iron vs Aluminum Cylinder Heads

thanks Billy
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post #15 of 23 (permalink) Old Jan 13th, 11, 1:50 PM Thread Starter
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Re: Cast Iron vs Aluminum Cylinder Heads

Ok answer this is an aluminum head prone to a leaky head gasket over iron?

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