Iron or aluminum heads?

warpd · Dec 28, 2005

I've heard that staying with an Iron head , even the stock heads with larger valves and a good port and polish will make more power than most aluminum heads on a stock short block , because of a loss of compression and the iron heads do a better job of keeping heat inside the combustion chamber. Is this true, has anyone else heard this? I realize you will lose a decent amount of weight from the front end, but besides that if I can get some gt40p heads and get them sent to a machine shop for some headwork and get larger valves installed I'd rather do that.

RacEoHolic330 · Dec 28, 2005

aluminum > iron

Michael Yount · Dec 28, 2005

Any thermodynamic benefit that the iron head may have is offset by being able to run more timing/lower octane fuel with the aluminum head, not to mention the 50-80 lbs. weight savings. 50 lbs. on our engines -- even more on big blocks.

Here's a very easy way to answer your own question. Go look at any type of racing (car - drag, autocross, rally, F1, sports car, etc. - motorcycle, snowmobile, trucks ---- ANY type of racing) and see what materials their heads are made out of. Unless they're required to run iron heads by the rules (almost always in classes where they're trying to either 1) remain stock or 2) save the competitors money) -- they ALL run aluminum heads. Now, if there were a performance advantage to running iron heads -- don't you think they would?

The vast majority of engines made globally over the last 30 years have had aluminum heads -- most engines produced in 2005 have aluminum blocks also. Cast iron heads and blocks are quickly becoming extinct. Darwin had it right.

90mustangGT · Dec 28, 2005

The only real advantage of an Iron head is the durability. They are less likley to warp if you run it too hot, but it's not a huge difference with today's quality alumimum heads.

The factory E7TE castings do have potential. I ran ported E7's by Thumper460 (Thumper Heads) and they worked pretty good. Many people on here running ported stockers with success, 25thmustang just has larger valves in them, running low-mid 12's. Like Michael Yount said, with an alumimum head you save weight, they distribute heat better, many advantages. They usually flow a lot better as well.

5spd GT · Dec 29, 2005

Yeah I saved about 35lbs with my heads over the irons

Aluminum is easier for a machinist to port as well...

Paul Perreca · Dec 29, 2005

IntenseBlue · Dec 29, 2005

Another vote for aluminum.

351LX · Dec 29, 2005

In the latest issue of Car Craft they do back to back dyno testing of a motor with iron and aluminum heads that both flow essentially the same.The horsepower was virtually identical so you can safely bury the old wives tale.

Michael Yount · Dec 29, 2005

5 spd - if those were for your 302 - you saved more than 35lbs. -- the weight savings is 23-25 lbs. per head on a small block Ford.

5spd GT · Dec 30, 2005

Michael Yount said:
5 spd - if those were for your 302 - you saved more than 35lbs. -- the weight savings is 23-25 lbs. per head on a small block Ford.

Shipping weight for the heads was 6x lbs. The iron heads are 100lbs. I didn't notice that much difference from lifting them (each head)...I was just going by the shipping weight compared to stock weight

Michael Yount · Dec 30, 2005

Shipping weight includes packaging -- you have to actually weigh the heads. You knocked about 50 lbs. off....as Martha would say - that's a good thing.

87'GTstang · Dec 30, 2005

With an even comparrison (flow numbers), an iron head will make more power than an aluminum. They due this due to a more uniform combustion chamber temp and they retain the extra heat that aids in more complete combustion. The point where aluminum makes up for it is the weight factor. Material for material, iron has aluminum beat by durability (by a long shot) and power output. Pound for pound, the extra power doesn't mean a thing due to the enormous loss in weight savings. Aluminum have a lot more advantages in the long run, but one needs to be very careful with them because they aren't so forgiving.

thumper460 · Dec 30, 2005

You WILL save weight!! And being able to pull 30 lbs off the front is good... but the HP to move the 30 lbs is maybe 3 HP!! move the batt to the trunk.. and your pretty much there!! Yes on the mag article.. the heads made the same power.. the same engine temp.. the same flow and runner CC's !! and they werent able to disprove the Alum vs Iron heat issue!!

It is really all in the wallet and what you really want from the car!! 12s?? either head will do that!! 11s?? working a stock head, but a ported set will make that happen!! low 11's ?? time to look for more flow in after market heads.. and then go with the wallet!! The rage is the AFR's !! they rock!! and so does the price!! plus the other "stuff" that goes with them!!

If the engine is good... get the N.O.S. going!! street a solid low 13 or 12 sec dailey driver (Iron head ported).. then spray to the low 11's or 10's !! and the cost of the ported iron heads AND the bottle is STILL less than the alum aftermarked set up!! and IF you locate the bottle with a little stealth... no one will Know till you blow their doors off!! LOL

Just me.............................

Thumper

bobcatv8 · Dec 30, 2005

FE vs. AL

One other angle that favors aluminum. Repair jobs. Repairing a cast iron head that ate a valve. It happens. After you've spent a small fortune in port and polish work on an iron head and a dropped valve goes through the combustion chamber, you will cry. Aluminum head takes a MUCH easier fix if the same tragedy occurs!

90mustangGT · Dec 30, 2005

Iron retains heat more than alumimum, therefore it might be bennificial to a lower compression N/A motor setup, but not for a higher compression setup. The truth is that alumimum are best for performance, mainly for the weight bennifit. The weight of an alumimum head is not half that of a factory iron, more like 3/5ths.

If someone wants some great street heads for a mild setup or someone just getting started in modding, Thumper460's ported E7's are excelent. I don't give a rats ass what anyone says, I had them with the double valve springs and it pulled to the rev limiter, hung up many alumimum headed cars, just suprised people. Really woke the car up. Passed emmisions with flying colors, made great power, same as stock below 3000rpm but after that is was a different car. I sold them for $400, which I could have gotten more, when I put them up for sale they were sold in less than 24hrs. No, I didn't "upgrade" for the alumimum stuff, but going onto another level, 347, getting really serious street/strip, Im looking at AFR205's. I honestly regret selling the Thumpers. I have a 306 sitting in the garage, could have made a great motor for something else.

If your near stock looking to upgrade, don't want to hassel of a race engine, remember this, many alumimum heads require other parts to make them work (stud mount rockers, longer pushrods, different header bolts, ect) and most people end up having to swap the springs anyways. A set of TFS/AFR which are the best, will run you a minumum of $1500 all said and done. Most sit over $2-3K when all is said and done. Alumimum heads are more picky.

5spd GT · Dec 30, 2005

Michael Yount said:
Shipping weight includes packaging -- you have to actually weigh the heads. You knocked about 50 lbs. off....as Martha would say - that's a good thing.

I know Michael

They were shipped in carboard box tight against the heads. Little hollow feeling pieces of wood on the ends. Total weight with the stickers...probably a lb or lb and a half.

Oh and two thermactor plugs...

bobcatv8 · Dec 31, 2005

I actually weighed both the stock '78 model iron 302 heads and the out-of-the-box {with studs & guideplates installed} Twisted Wedge heads I put on my wagon years ago. There was exactly 24 lbs. difference per head.
They made my car 48 lbs. lighter and 8 tenths quicker right out of the box!

5spd GT · Dec 31, 2005

Weight difference between 78 and 93 heads?

IndyBlk5.0 · Dec 31, 2005

i run irons, and i run 14 degrees timing and 87 octane all the time... no detonation, if anything im rich... i like mine

Iron or aluminum heads?

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