Iron 408 versus aluminum 427
10-16-2008, 09:38 AM
#1
Iron 408 versus aluminum 427 I'm trying to decide which direction to go between an iron 408 and aluminum 427 and interested in some opinions. Current set up is listed in sig, my camaro is not a DD, just a weekend toy. I take it to the drag strip occasionally and more recently road raced it... which led to me spinning a rod bearing. I like the idea of a setup that will still give me the flexibility to do both types of racing. With either I'm going to go with a better intake manifold and 1 7/8 inch primaries.
What I know about each at this point are as follows:
Iron 408
Alunimum 427
Anything I'm missing here? Thanks for the input.
What I know about each at this point are as follows:
Iron 408
- ~65 pounds heavier
- less expensive ($1,300 or so?)
- arguably more reliable
- amenable to power adders going forward (although no plans at this point)
Alunimum 427
- lighter weight
- more expensive
- possibly less reliable(?)
- no power adders
- sexier (history of the 427 displacement)
- should make more power because of the 19 cube advantage(?)
Anything I'm missing here? Thanks for the input.
10-16-2008, 10:12 AM
#2
CUBES RULE!! Todays aluminum can handle quite abit. If you get it built and tuned properly, there should be no issues with the aluminum block, if weight is your issue. GM HighTech had a great section on LS style short blocks and complete packages for under $6500.00, with good internals. Many of them were the vendors on the right ---->. I believe the cast iron motor complete is 99lbs heavier, but not sure. The racing is coming to an end here in Michigan. I would maybe make a decission on the short block and wait and see if and when GM plans on releasing the LSX heads through the winter. They might be the bomb and less expensive! With the right choice of parts, that 19 cubes could net bigger power that would justify the price difference. The smaller, (1 7/8"), primaries will give you better low end out of the corners or off the line, but don't count out the 2". Be sure you match the heads, cam, intake, throttle body, compression, and exhaust for the rpm range you are trying to attain. Good Luck.
Last edited by 382ssz28; 10-16-2008 at 10:18 AM.
10-16-2008, 10:19 AM
#3
I have that copy of GMHTP and have looked at that short block article several times, it had some good info. I fairly comfortable with the builder I've selected...HKE in Houston. I'm just trying to decide what I want to have built. Generally speaking, I want to go as big as is financially doable and reliable.
10-16-2008, 11:22 AM
#4
The L92 427 is a non power add engine. HKE builds all my engines you have made a good choice. The 427 will be reliable, thats not an issue. What you need to look at is your budget and HP goals. Bigger cubes makes more power.
If your thinking about n2o or boost then the 408 is your engine. The L92 427 will be n/a only and Erik will tell you that.
If your thinking about n2o or boost then the 408 is your engine. The L92 427 will be n/a only and Erik will tell you that.
10-16-2008, 01:03 PM
#5
The L92 427 is a non power add engine. HKE builds all my engines you have made a good choice. The 427 will be reliable, thats not an issue. What you need to look at is your budget and HP goals. Bigger cubes makes more power.
If your thinking about n2o or boost then the 408 is your engine. The L92 427 will be n/a only and Erik will tell you that.
If your thinking about n2o or boost then the 408 is your engine. The L92 427 will be n/a only and Erik will tell you that.
10-16-2008, 01:39 PM
#6
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Why do you limit the iron block to being a 408? It can be a 427 if the block checks out okay if not it can still be alot bigger then just a 408 then you have all the reliability and the big cubes and still only sacrifice adding 65 lbs up front. Besides if its only a toy and you enjoy road courses opt for chrome moly k-member and a-arms you have already lost part of the weight that you gained with the added bonus of being able to tune in your cars handling as well. That is just what I would look into. Check out Weber Racing they are a sponsor on here I just talked to them last week about build a 427 iron block for a buddy's car they fully CNC the blocks for clearance on stroker builds.
10-16-2008, 03:16 PM
#7
Why do you limit the iron block to being a 408? It can be a 427 if the block checks out okay if not it can still be alot bigger then just a 408 then you have all the reliability and the big cubes and still only sacrifice adding 65 lbs up front. Besides if its only a toy and you enjoy road courses opt for chrome moly k-member and a-arms you have already lost part of the weight that you gained with the added bonus of being able to tune in your cars handling as well. That is just what I would look into. Check out Weber Racing they are a sponsor on here I just talked to them last week about build a 427 iron block for a buddy's car they fully CNC the blocks for clearance on stroker builds.
The iron 408 was going to be an LQ9 block I think (iron version of the aluminum LS1, right?). So you're saying that you could go 427 on the LQ9 block - if it checks out? I don't remember seeing any iron 427 options out there.
For my proposes I don't think the extra 65 pounds will be a huge deal, I just drive for fun, not trophys.
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10-16-2008, 03:27 PM
#8
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The 427 Iron block is pushing it according to most. That is/was my plan. I think you can "safely" bore to 414 ci or 418 ci, not 100% sure though. I'm going with a forged 427 Stroker kit in the Iron 6.0 block. Should be fun 
10-16-2008, 03:45 PM
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But you are definitely correct about the sexyness factor with the "427 ci". If I do a 427 Stroker kit, but only come out with a 418 ci, it's still gonna be called a 427 if you ask me.
10-16-2008, 03:48 PM
#13
The L92 is a 4.070 bore with out maxing it out. The LQ9 has to be bored to is maximum and then sonic checked to make sure the integrity is still there. Your talking about the cost of block here.
$700 vs $1400 so for that $700 do you want a lighter block that isn't pushed to it limit?
Its personal choice. Some guys dont like to push them to the limit other guys do and dont have issue. Either or it's a no power add engine with the bigger stroke.
Whats the cost of the LQ9 427 and what are the parts used in it if you want to make a good comparison.
They both use a 4.100 " stroke crank.
$700 vs $1400 so for that $700 do you want a lighter block that isn't pushed to it limit?
Its personal choice. Some guys dont like to push them to the limit other guys do and dont have issue. Either or it's a no power add engine with the bigger stroke.
Whats the cost of the LQ9 427 and what are the parts used in it if you want to make a good comparison.
They both use a 4.100 " stroke crank.
Last edited by 99blancoSS; 10-16-2008 at 03:54 PM.
10-16-2008, 04:03 PM
#14
Personally, it killed me to do a 382, (4.0" crank and 3.905" bore, 6.125" rod), but my 16 year old daughter woke up with psoriatic arthritis and fibro mialgia and I didn't know what the out come would be. It took the all of the specialists around the country 7 months to figure it out. I had already bought the crank, rods and bearings, and I was trying to make a choice on the block when this happened. The car couldn't just sit there and my consience was killing me, so I did 'er cheap as possible. She's getting by OK now. The cold weather gets to her, but she's a trooper. Anyway, is a 4.125" bore to big for the LQ9? I never checked. I would look real hard at the aluminum block. Regardless what you race, the balance would be awsome! GO 427, you "sexy biotch"!
PS, I think a 427.8" is 4.125" bore X 4.0" stroke, I think you will have to notch the block
PS, I think a 427.8" is 4.125" bore X 4.0" stroke, I think you will have to notch the block
Last edited by 382ssz28; 10-16-2008 at 04:13 PM.
10-16-2008, 07:57 PM
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check this iron 427ci at Weber http://weberracing.net/Engine-Type-G...duct_info.html
10-17-2008, 08:44 PM
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I'd like to hear more input from the guys that have done this reliably.
I just had a LQ9 block taken in to be machined, and it sonic'd at .104" wall thickness. The machinist said that he'd never taken a block below .80, and rarely under .90". With the .065 bore for the 415ci stroker, the wall thickness would be .72". He said that I would be playing with fire at that point.
Not good in his eyes.
I consulted another motor builder, and they said that .065" bore is fine with that sonic'd wall thickness.
So what do you all think? That link posted above takes you to a website that says that they go .070" bore after sonic testing. So if they had my block, would it be to their specs, and last in a reliable offroad race vehicle?
Motor builders? Thanks in advance.
I just had a LQ9 block taken in to be machined, and it sonic'd at .104" wall thickness. The machinist said that he'd never taken a block below .80, and rarely under .90". With the .065 bore for the 415ci stroker, the wall thickness would be .72". He said that I would be playing with fire at that point.
Not good in his eyes.
I consulted another motor builder, and they said that .065" bore is fine with that sonic'd wall thickness.
So what do you all think? That link posted above takes you to a website that says that they go .070" bore after sonic testing. So if they had my block, would it be to their specs, and last in a reliable offroad race vehicle?
Motor builders? Thanks in advance.
Last edited by whitebro; 10-18-2008 at 10:19 AM.
