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Re: Iron heads vs. Stealths
[Re: ademon]
#440867
08/17/09 02:02 PM
08/17/09 02:02 PM
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Joined: Aug 2004
Posts: 3,392
cheshire, ct
davesmopars
master
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master
Joined: Aug 2004
Posts: 3,392
cheshire, ct
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if everything is the same, iron heads make more power
Keeper of the 440 M code Cuda registry
mcodecuda@yahoo.com
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Re: Iron heads vs. Stealths
[Re: davesmopars]
#440868
08/17/09 02:37 PM
08/17/09 02:37 PM
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Joined: Nov 2004
Posts: 843
Suffolk,VA
ireland383
OP
super stock
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OP
super stock
Joined: Nov 2004
Posts: 843
Suffolk,VA
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The 346's have the stock valve sizes. I thought I would benefit with the larger valves of the stealths, also the weight factor. I'm not sure how much can be shaved off the stealths with running a domed piston. I'm sure I'm close to 10 to 1 now. One other thing I thought would be better is the closed chamber of the stealths.
Last edited by ireland383; 08/17/09 02:56 PM.
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Re: Iron heads vs. Stealths
[Re: davesmopars]
#440869
08/17/09 03:04 PM
08/17/09 03:04 PM
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Joined: Jul 2006
Posts: 4,319
Puyallup, WA
StealthWedge67
master
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master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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Quote:
if everything is the same, iron heads make more power
Guys, are you kidding me? Seriously...... First off, the 346 head is an open chamber, so going to a stealth head would up the compression significantly.
Secondly, I don't even know what to say..... a stock set of 346 castings vs. a set of Stealths?? Is this a trick question? Is there something I'm missing? I'd say: no comparo. There's no way the 346 even come close.
Now, We need to know more about the combo. If you don't have the flow abilities on the intake side, or the exhaust side, to make use of the flow capabilities of the new heads, then maybe you wouldn't feel a difference ?? Tell us more about the entire combo.
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Iron heads vs. Stealths
[Re: ireland383]
#440871
08/17/09 03:28 PM
08/17/09 03:28 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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Actual real world tests show very very little if any power loss from iron vs aluminum. I have seen several dyno tests of heads in iron and alumnium even as can be like CNC ported and there was no real world differance in the power, 2 or 3 tops on a 350 chevy. The aluminum head allows more compression, it does NOT require more compression.
As for your combo feeling weeker it could be a few things, mabey timing was not optimised for the new heads(they will need less timing) and the carb could be running lean with the extra airflow. Mabey the car is hooking better do to weight so now you can not roast the tires like you were. Mabey the tq converter needs adjusted also. Several things to look at before jumping to blame the heads. If there is a problem with the heads it would show up in a leakdown test(bad valve job).
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Iron heads vs. Stealths
[Re: davesmopars]
#440872
08/17/09 04:35 PM
08/17/09 04:35 PM
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Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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Power band and torque curve most likely changed. With the larger valves the bottom end torque could have changed. My 11.70 Pontiac felt like a high 13 second car because the torque curve was so flat. Maybe butt o meter needs recalibration? 
Allen
Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first.
Life was a little easier when I was just a wrench.
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Re: Iron heads vs. Stealths
[Re: HealthServices]
#440873
08/17/09 06:33 PM
08/17/09 06:33 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Give all the details of the engine. What cam? What intake? headers? convertor? gearing? carb?
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Iron heads vs. Stealths
[Re: HotRodDave]
#440880
08/17/09 07:44 PM
08/17/09 07:44 PM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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Quote:
Actual real world tests show very very little if any power loss from iron vs aluminum. I have seen several dyno tests of heads in iron and alumnium even as can be like CNC ported and there was no real world differance in the power, 2 or 3 tops on a 350 chevy. The aluminum head allows more compression, it does NOT require more compression.
 I also remember reading an article where they used an identical set of aluminum and iron heads on a chevy build and they dynoed within a couple hp/torq of each other.
But, going from stock small port heads to bigger port aftermarket heads could have costed you some low end power due to a drop in port velocity. Also your new heads could be flowing enough more that you're leaning out under WOT.
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Re: Iron heads vs. Stealths
[Re: StealthWedge67]
#440881
08/17/09 10:15 PM
08/17/09 10:15 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Quote:
Quote:
Your running a dome piston with closed chamber heads ?? How far down in the hole are the pistons ? Ron
http://kb-silvolite.com/performance.php?action=details&P_id=327
He's got the right piston for these heads, Ron. KB400's are more of a flat-top with a dome section above the valves only. Pretty much designed around a closed chamber head. You can run these at zero deck with closed chamber heads.
Ok I should have looked at the piston first. Thanks , Ron
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Re: Iron heads vs. Stealths
[Re: StealthWedge67]
#440882
08/18/09 11:15 AM
08/18/09 11:15 AM
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Joined: Feb 2003
Posts: 8,020
Pangaea
B5 Bee
master
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master
Joined: Feb 2003
Posts: 8,020
Pangaea
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Quote:
Quote:
if everything is the same, iron heads make more power
Guys, are you kidding me? Seriously...... First off, the 346 head is an open chamber, so going to a stealth head would up the compression significantly.
Secondly, I don't even know what to say..... a stock set of 346 castings vs. a set of Stealths?? Is this a trick question? Is there something I'm missing? I'd say: no comparo. There's no way the 346 even come close.
Now, We need to know more about the combo. If you don't have the flow abilities on the intake side, or the exhaust side, to make use of the flow capabilities of the new heads, then maybe you wouldn't feel a difference ?? Tell us more about the entire combo.
That's a correct statement, everything the same (ports, valves, combustion chamber), an iron head will make more power.
It takes about a 1 point increase in compression, with everything else the same, for aluminum heads to make the same power.
As fas as 346 vs Stealth, the Stealths advantages still should overcome any power loss from the use of aluminum. I'd advance the timing 2 to 4 degreees till the Stealth heads can be cut or pistons are changed. More timing can be used as a crutch till the compression is raised.
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