I have IRON heads!!!

[Malice]

I was pulling apart my camaro today to install my headers, and I noticed I have F@cking iron heads!!!

THe casting # is 12554290. I looked them up. THey are off of an LT1 style reverse cooling 350sbc from 1994-96. They are truck heads.

Those flow alot worse than regular alum. LT1 heads, right?

I've always noticed that the car is a dog at high rpm, and my timeslips prove it. the car runs mid to high 9's in the eigth.

[krayzie7th]

damn that freaking sucks.

[94zgreenmachine]

I was pulling apart my camaro today to install my headers, and I noticed I have F@cking iron heads!!!

THe casting # is 12554290. I looked them up. THey are off of an LT1 style reverse cooling 350sbc from 1994-96. They are truck heads.

Those flow alot worse than regular alum. LT1 heads, right?

I've always noticed that the car is a dog at high rpm, and my timeslips prove it. the car runs mid to high 9's in the eigth.

They aren't truck heads... they came off an Impala SS/ Roadmaster, etc. As far as flow, they are probably even in stock form. They are heavier.....

[94zgreenmachine]

Your iron heads were actually very good and the vortec heads were based on the iron lt1 head. Don't quote me, but I believe your iron heads will outflow the aluminum castings in STOCK form. The down side is probably less compression.
Google "LT1 iron head". A ton of info will come up......

[BrianEsser]

It's true. Given the choice. I'd take the iron heads (and do have them on my engine). They can be ported and can be made to flow more than their lighter weight counterparts. The only real advantages with the aluminum over the iron is weight and they help prevent detonation due to the higher compression ratio of the LT1 by dissapation of heat better. They flowed around 212cfm bone stock I believe. Compression ratios were the same I believe.

Your car wouldn't be any meaner with aluminum heads, well no more than take a few lbs off it would do. Nothing you would notice. You have something else wrong, or it's in your head.

[94zgreenmachine]

I can't find anything on the chamber size but all I can find is 10:1 and that is with 87 octane.

[Adam]

Yes in stock form the iron head outflow the aluminum ones but they weigh about 55lbs more on the nose of your car. Personally I'd take the weight savings.

[Malice]

I'm talking about this on CZ28 as well. Everyone seems to agree that I have Impalla SS heads, and that they flow a little better than the alum heads.

I didnt' check the block casting #, but I'll bet I have an entire engine out of an impala. The car is slow at high rpm. I believe I have an impala cam. The car idles at 22" of vacuum. THat is REALLY high. My old 3.8L v6 used to idle at 19".

I wish I could find out what my compression ratio is, to find out if I need to be using premium.

[94zgreenmachine]

Your block will be the same. look for a 327 cast in the side of the block not that it matters much as all LTX blocks will have this on it, including 4 bolt blocks.. There really isn't a difference between motors except for the cam and head material. They should all have vented opti's ... From everything I could find, it seems to want 87 octane

[Malice]

Your block will be the same. look for a 327 cast in the side of the block not that it matters much as all LTX blocks will have this on it, including 4 bolt blocks.. There really isn't a difference between motors except for the cam and head material. They should all have vented opti's ... From everything I could find, it seems to want 87 octane

If all the blocks are the same, then they all have 10.1:1 compression, right?

I'm basically just trying to figure out if this is a blessing in disguise, or yet another pitfall.

I've got a new set of valvesprings waiting to be installed, and an LT4 hotcam on its way.

When I first saw the iron heads, I said to myself: "there is no way I'm wasting time installing valvesprings and sprucing up junk iron heads."
Now that I know they flow a little better, I might go ahead and install the springs on them after all.

If the B-body and F-body blocks are the same, then I should still have 10:1 compression. WHen I pull out the really really tiny b-body cam, and put in a hotcam, I should have quite a power boost!!!!!!

[94zgreenmachine]

If all the blocks are the same, then they all have 10.1:1 compression, right?

I'm basically just trying to figure out if this is a blessing in disguise, or yet another pitfall.

I've got a new set of valvesprings waiting to be installed, and an LT4 hotcam on its way.

When I first saw the iron heads, I said to myself: "there is no way I'm wasting time installing valvesprings and sprucing up junk iron heads."
Now that I know they flow a little better, I might go ahead and install the springs on them after all.

If the B-body and F-body blocks are the same, then I should still have 10:1 compression. WHen I pull out the really really tiny b-body cam, and put in a hotcam, I should have quite a power boost!!!!!!
No, compression difference will be in the head chamber and the head gasket used. I can not find any info on the head chamber size. An easy call to GM or a speed shop should be able to answer that for you. Stock LT1 f-body were at 10.4:1 or 10.5:1. It has been so long since I have dealt with stock, I don't remember the exact compression.My latest is at 12.1:1 and it WILL run on 93 octane....

[BrianEsser]

Then they are the same as mine which came from a 94' Police Caprice has 10.4:1cr.

It's the cam holding you back, not the heads.

[Malice]

Then they are the same as mine which came from a 94' Police Caprice has 10.4:1cr.

It's the cam holding you back, not the heads.

THank you!!

THat is the key piece of information I wanted! I guess I'll go ahead and respring these heads then, and get ready for my hotcam install.

[94zgreenmachine]

Then they are the same as mine which came from a 94' Police Caprice has 10.4:1cr.

It's the cam holding you back, not the heads.
Where do you get that CR from?

[LT1_Fireman]

Your iron heads were actually very good and the vortec heads were based on the iron lt1 head. Don't quote me, but I believe your iron heads will outflow the aluminum castings in STOCK form. The down side is probably less compression.
Google "LT1 iron head". A ton of info will come up......

He is right they do outflow in stock form... the down side is they heat soak very bad, they are heavy,and they cost more to be ported.

[BrianEsser]

Where do you get that CR from?

i was off, it is 10.5:1 not 10.4:1, but either way they are the same.

All LT1 heads used small combustion chambers to get the higher compression ratios with flat top pistons; the 350s had a 10.5 to 1ratio and the 265s had a 9.8 to 1 ratio.

Taken from here: http://www.projectlt10.com/content/modules/tinycontent/index.php?id=32

[94zgreenmachine]

i was off, it is 10.5:1 not 10.4:1, but either way they are the same.

All LT1 heads used small combustion chambers to get the higher compression ratios with flat top pistons; the 350s had a 10.5 to 1ratio and the 265s had a 9.8 to 1 ratio.

Taken from here: http://www.projectlt10.com/content/modules/tinycontent/index.php?id=32
For some reason I couldn't just accept that. I knew the head was the basis for the vortec heads and they were very efficient but being cast iron I still wouldn't have thought they would bring compression to 10.5:1 .
The whole old school 9:1 with cast heads and aluminum is good for a 1 point increase in compression, doesn't hold true here. I knew the reverse cooling was good for about a .5 point increase.
Thanks for the info.

[hempkat94z]

I could be wrong but i believe the OEM head gasket on the impala was thinner to get the 10.5 compression. Double check that tho.

[IronOutlaw]

Yeah the impala head gaskets are thinner.

[1badz]

The Iron heads flow a lot better in stock and ported form, and also put less stress on the headgaskets because the heads are relatively made up of the same material the block is made up of, therefore allowing the block and heads to warm up and cool down at the same rate. Iron heads also seal better from what I heard.

[phantomzer0]

So overall, this is a good thing for Malice... :)

[JoeliusZ28]

its subjective. pros and cons...

Its too bad they never made an aluminum casting of a reverse cooled vortec head.

[Malice]

So overall, this is a good thing for Malice... :)

That is the conclusion I have drawn as well. I probably won't ever pull them off to upgrade them, so it's good that they are a little better flowing that stock. Methinks they will be very respectable with my hotcam. Furthermore, I understand that they can improve longevity of the engine since the heads and the block expand/contract due to temp at the same rate. I plan on driving this beast to 200k miles.

It stinks that they are 55lbs heavier than the alum heads, but I can live with that. Honestly, whats 55lbs on a 3400lb street car?(weight nazi's need not respond. That was a rhetorical question)

I have personally seen thier heatsoak problem. My car gets steadily slower during a race night due to the heat soak. I'll just fashion up a fan switch or something. I already have a cold tstat, and it helped.

I went ahead and installed lunati .630 valvesprings on them, in prep for my hotcam.

[BrianEsser]

I was gonna say, if not you could toss those 'junk' heads my way. :devil::D

[Silversixspeed]

Did that car ever had a "junkyard" motor put in it? It sounds to me like someone previously switched motors in it, and found one from an Impala?

I'm putting an Impala motor in my Trans Am right now, iron heads and all. Good to know there ARE some pros to "outweigh" the cons :cool: