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Discussion Starter #1
ok,ok,ok,!everyones telling me not to buy aluminum heads for my 350.short life i.e. gaskets,sealing,etc.hey!what the hair is on half the new chevy motors and it seems to be all! the chevy line before long.aluminum!different expansion rates are most often specified as the main culprit.next in line is the thermal differences,i.e. iron does'nt rob the motor of necessary heat for max efficiency.then i read a alum. vs. iron head shootout where all factors are balanced to provide a fair fight[though everyone is expecting the iron heads to win] and guess what?the alum heads win!any and all input on this would be great!jimm
 

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Well I guess things have improved somewhat since I have played with aluminum heads. They sure where a pain in the butt back in 85. I learned that unless I was willing to o-ring the block it was not worth the hassle. I'm talking high compression daily drivers that get driven in all kinds of weather and all kinds of traffic. If they made aluminum blocks cheap I might be a believer, sure would be nice to slip in a new set of sleeves when you want to freshen up. Biggest problem I had was uneven gasket compression on the heads no matter how perfectly straight the heads were decked or if I used studs or not. If there was a steel torque plate across the head under the valvetrain I would be happy. I still prefer good old cast iron for the even expansion characteristics and stable valvetrain base it provides. Overhead cams would solve most of the problems as would torque plates around each cylinder, but unless there has been a alloy engineering breakthrough or the laws of physics has been appealed I wouldn't use them on a daily HIPO driver. It seems the repeated heat cool cycles will eventually cause you grief, keeping headers tight is even worse with aluminum in my expierience. If you get them cheap I say go ahead but if I had a choice cast is where I would spend my money. At least you wouldn't have to worry about dropping a valve seat if you run her a little lean. Things may have changed, maybe some other members have a head that they had good expieriences with?
 

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any article you read in a magazine is a paid advertisement pushing parts and people for fame and fortune.if you want a build it once engine go with iron,if you want a higher compression longer duration pumpgas engine use the aluminum and accept the pitfalls.the factries use aluminum to raise compression and lighten the vehicles to conform to CAFE standards the same with all the plastic and thinner sheet metal...not good for moving giant oaks or attacking busses.
 

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I would not use AL heads on a daily driver. The durability is well worth the added weight. Go with cast iron!
 

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Discussion Starter #5
4jawchuck,tom,57chevyman thanks! i think was trying to talk myself into trying them mainly for the "nasty" factor. any tips on head manufacturers?how about airflowresearch?thanks again,jimm
 

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Well I've nver switched to aluminum heads on any of my engines yet. That includes a 71 Vega I had with a 350-4 bolt mains,M22 trans,and a 12 bolt in the back that ran consistant 12's in the quarter mile with pro-trac N50's and full exhaust and you guessed it, iron heads. If the engine came with iron heads that's how I keep it. I have to wonder why Fords been putting the 3.0 OHV engine in its vehicles for years and they rarely ever blow head gaskets yet the 3.8 OHV engines blow head gaskets if you look at them wrong. Lets see----3.0 engine,iron heads----3.8 engine,aluminum heads----you figure it out, Ford certainly can't.
 

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Aluminum heads wick off heat better than iron. For this reason heat at the combustion chamber tends to be lower and therefore detonation is less apt to occur. Hence there are two benefits to aluminum heads, they run cooler, you can use a higher compression ratio and they weigh less. You like how well I count? I don't buy any of the durability slams on aluminum heads. If installed properly, they should seal well and none of the surfaces are wear surfaces so they should last as long if not longer than iron. The only negative I associate with aluminum heads is that they cost more....but may be worth the money if you are willing to spend the money to get the potential for added hp. If you don't care about the last ft pound and last hp issue and are willing to accept a little less in both departments, I would save the money and buy the iron. But the manufacturers of high mileage vehicles use aluminum because the lower weight allows the car to get better mileage for the life of the head.
 

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My 57 hardtop has a 327 with 87 corvette heads and so far its the greatest. I've only put about 1000 miles since installing engine.
 

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Now that I think about it I'm not sure about the year, but they are corvette alum. center bolt heads. Guess I'm getting old, they say your memory is the first to go....
 

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Discussion Starter #10
ok.ok,ok!can we hear from someone currently running alum. heads?ihear you guys saying that they are selling mags/corporate fuel economy[avg. ],etc.hellooo!there are gm rigs out there working their %$ss off daily,[100000 miles]with alum heads and no associated[alum.] problems!sorry, too much attitude,jimm
 

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Gotta throw my hat in the ring...personally, I prefer iron heads. I've run both and it seems the iron holds up better/longer. Even useing never-sieze on every fastener, it seems the alum. threads just don't hold up as long, especially at the sparkplugs. Maybe because of the heat generated in the plug...I don't know. What I do know is if you go with the alum. heads have plenty of never-sieze on hand. It's cheap insurance against galling at the threads and will give you a truer torque if you put it under the headbolt washers. It doesn't take alot of the stuff, but it's worth the extra effort.
 
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