Aluminum or Iron Heads???

wickedmach1 · Jun 26, 2004

I know this is a common question but my question is a little different. I am building a 393 stroker with HP estimates around 480 - 500 for my '70 Mach 1. If I bought iron heads and had them ported (not worried about extra cost), would there be any benefits over aluminum? I planned on using AFR 185's on the 393 but have heard stories about aluminum warping and not being as strong. I understand the benefits of aluminum being lighter and helping reduce detonation, but if the iron heads flowed up to par with the AFR 185's, which would be preferred and why? If iron is the answer, which would you recommend and why? Thanks for the help.

RajunCajun · Jun 26, 2004

aluminum is lighter is only real advantage and otherwise the transfer of heat is higher in aluminum

10secgoal · Jun 26, 2004

Aluminum is better in every way. It warps easier yes, but you still have to abuse them to do it. A completely hogged out set of irons won't flow like afr's or tfs

D.Hearne · Jun 26, 2004

You'll NEVER port factory iron heads to flow on a par with AFR's ( or just about any other aftermarket aluminum head) so you can kiss that estimate of 480-500 hp out the door. You could go with a set of World Products , Roush or Dart iron heads though.

2bav8 · Jun 26, 2004

There is probably only one set of cast iron heads that might be able to flow what AFR 185s can and I'm not sure they make them anymore (World Products, think they are/were Rouch Heads now). I sure wouldn't want to use them on a 393 though. Still too small. I'd want a set of AFR 205s or Edlebrock Vic Jr. for that kind of cubic inch usage.

As for Al heads warping, they would only warp if you really over heated the motor, which a cast iron head would as well. As an example, AFR uses a 3/4" deck, that's thick!!!

Also, with the compression that 393 is going to have, the Al heads will much more kind with the poor excuse we have for fuel these days.

RajunCajun · Jun 26, 2004

Some Interesting reading

FordMuscle Article

They obviously proove that TFS heads flow more with AFR right behind him

Route666 · Jun 26, 2004

They're only 165 AFRs though, 185s and 205s flow more, and you'd need 205s to utilise the potential of a 393.

wickedmach1 · Jun 26, 2004

So AFR 205's would be the better fit with the 393? I have been round and round on which to use and still don't know. I don't want to loose my bottom end torque. I also need to pick a intake manifold. Don't you also need special headers for the 205's due to the port locations being different from stock? Someone please help. I am getting close to buying my parts and I still am confused.

D.Hearne · Jun 26, 2004

If you reallly want to maximize the bottom end of the performance curve on that 393, then go with the smaller heads. The higher flowing heads will only raise the HP and torque peak farther up the rpm range. Even 165's will perform on a 393, only difference from 205's would be the HP anf torque peaks will occur at a lower rpm range. Bigger isn't always better, depends on what you want the engine to be.

Denny Wiedman · Jun 26, 2004

cast alum

i have the roush200 heads on my 408w 69mach1, .500 lift 250 .in 180.ex, .600 263 .in 186 .ex, int port cc 206 chamber 67.5, before these heads i had on the old world sr heads cast iron also they flowed a lot less than these do and made 400 horses at the flywheel and 400ft lbs@ 3100 rpm's with the stealth, now i am using the vic jr manifold and bigger heads and cam, im looking at 475 to 500 hp with this new combo i hope with tuning, i was going to use the alum heads but getting into trouble with headers with these bigger heads, as you know not much room in that engine bay,so im waiting for somebody who has headers that will fit in there before i spend big bucks for heads, i was going to get the afr 185 heads and mill them down a bit with the right cam and manifold you'll get 500 hp out of it, if your not going to race your mach and do driving on the street these cast iron heads will make power i have chasis dyno numbers to prove it, torque is what you need for street driving not high rpms, i never see over 4500 rpms on the street, look at your driving and go from there, AFR 185 might be my next head because they have stock .ex port location.

Great68 · Jun 26, 2004

RajunCajun said:
Some Interesting reading

FordMuscle Article

They obviously proove that TFS heads flow more with AFR right behind him

Keep in mind, the AFR's and other heads they tested used 1.90 valves while the trick flows used 2.02 valves.

Route666 · Jun 26, 2004

D.Hearne said:
If you reallly want to maximize the bottom end of the performance curve on that 393, then go with the smaller heads. The higher flowing heads will only raise the HP and torque peak farther up the rpm range. Even 165's will perform on a 393, only difference from 205's would be the HP anf torque peaks will occur at a lower rpm range. Bigger isn't always better, depends on what you want the engine to be.

Sorry for a little hijack, but having said that D.Hearne, would 165s also be a better option for a 331 than 185s? For a streetable application that is, although the motor would be built for 8krpm, limited to 7 or so.

2bav8 · Jun 26, 2004

For a 331 spinning 7,000 RPM I'd use a bigger head than a 165.

You gotta remember, with those extra cubic inches, bigger crank throw and longer rods you're going to make more torque at lower RPMs than a 289 or 302. The bottom end power is going to be more impressive, even with larger cylinder heads, cam etc (to a point).

allcarfan · Jun 27, 2004

yawn.....

im glad i have some TWs that flow 305/230 @ .600"

D.Hearne · Jun 27, 2004

Route666 said:
Sorry for a little hijack, but having said that D.Hearne, would 165s also be a better option for a 331 than 185s? For a streetable application that is, although the motor would be built for 8krpm, limited to 7 or so.

Yes they can be used, like I posted before, bigger isn't always better. Just depends on what you expect from the motor and where you want the power curve to be. Better flowing heads have the same effect as a bigger cam. Just because a motor has more cubes, doesn't mean you HAVE to run the best flowing heads on the market or brand A heads over brand B just because brand B flows more.

85GTlover · Jun 27, 2004

D.Hearne said:
You'll NEVER port factory iron heads to flow on a par with AFR's ( or just about any other aftermarket aluminum head) so you can kiss that estimate of 480-500 hp out the door. You could go with a set of World Products , Roush or Dart iron heads though.

This may not be true.....I read the article posted and many others and have read the only real advantage is weight and you can lower your compression ratio. As for the flow if the porting and specs were all the same.....Why would there be any difference? Aluminum is more popular mainly because of weight and they seem to be the "chosen" ones.

I someday will go aluminum but I will try for some late 90's Explorer heads and port and get a 5 angle valve job and try those for now. Cheaper is better for me.

D.Hearne · Jun 27, 2004

85GTlover said:
This may not be true.....I read the article posted and many others and have read the only real advantage is weight and you can lower your compression ratio. As for the flow if the porting and specs were all the same.....Why would there be any difference? Aluminum is more popular mainly because of weight and they seem to be the "chosen" ones.

I someday will go aluminum but I will try for some late 90's Explorer heads and port and get a 5 angle valve job and try those for now. Cheaper is better for me.

The reason you cannot port factory iron heads to flow like the majority of aftermarket iron and aluminum heads that are now on the market is simple--- you'll hit water. There just isn't enough metal there to make the factory ports match the aftermarket heads. The chamber shape also comes into play here too. You can't reshape the factory chambers to match a different shape without welding new material there first. To get the ports to match the aftermarket ones, you'd first have to completely recast a new head. You can TRY to get factory heads close to aftermarket ones, but by the time you get them to flow close to them, you'll have spent more money and time than if you had just bought the aftermarket ones first.

Route666 · Jun 27, 2004

Thanks D.Hearne. Strangely, what you said was basically what I said in another thread, but I never applied it to my own means. Big cams will give you container-ship loads of power at 40 bazillion rpm, but building a motor to actually take off from a standstill without resorting to drag race style take offs is another thing.

Thanks also 2bav8, I agree, and while an engine with those 165s may be really good, and extremely street-able torquewise, 185s would free the extra potential from the motor and possible even gain some low end, and definitely not lose anything overall.

TT670 · Jun 27, 2004

RajunCajun said:
Some Interesting reading

FordMuscle Article

They obviously proove that TFS heads flow more with AFR right behind him

It isnt always about what head flows more, numbers are only numbers. Its about what head makes the best most useable power. AFR hands down is a better out of the box head than a TFS. If I were building a 393-427 stroker Id be using a 205, any of these engines make enough torque that youre not going to notice any small losses that may occur.. a poor camshaft choice would be much more of an issue. 185s are just about a perfect 331-347 head

wickedmach1 · Jun 27, 2004

So what you are saying is that because of the added cubes of the 393, the loss of low end torque by using the AFR 205's will not be noticed? Can anyone explain why? I also know with the 205's, custom headers will be needed due to the location of the exhaust ports. This is not really a problem since I want to use 1 3/4" shorty headers and can't find any. I will have to have them made. I see 1 3/4" longtubes all day long. If I were to go with the 205's, what is the appropriate intake manifold? If I go with the 185's, what is the proper intake manifold? Remember, STREET CAR. Thanks for the help.

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