My gift to you for Thanks Giving I threw "theory" in there for you deliberately. ;)
I thought it nice to offer you a "get of jail card", because once you read those facts, there's no further retort. :p
You're welcome and enjoy your holidays :)

I'm a statistical analysis kinda guy with real world data, independent and dependent variables, etc. Once you have the study setup with multiple FE engines, both cast iron OEM blocks, Shelby, Pond, BBM, Side Oiler Garage aluminum and cast iron blocks all with the same parts but for the block and related pieces that go with the block and then run them all on the same dyno in the same atmospheric conditions and if the various alloy blocks make a statistically measurable difference in HP, then and only then will I believe it.

Otherwise, just theory, chemistry sets and hot air. Until that happens, I don't want to hear about books and hearsay. No "get of jail card" necessary. Thank you very much.

I said it before. I weight 170lbs. No lbs to loose. So I'll let my block do it.

It's been done before, but not at the same time. Barry has built a motor with an iron block at got x amount of hp. He has defiantly built the same motor using the same parts but with an aluminum block. And got different hp numbers. Atmospheric measure can as well be the same. I'm sure he measures and monitors that when he does dyno pulls. I bet Blykins has built hundreds of FE motors and with the same parts but different blocks under the same atmospheric conditions but on different days. I don't think the idea that it has to be done at the same time means that much. So let's just say it has been done by many builders of FE's. And each time they say iron makes more power.

Seriously, please no more online posts of the cast iron's superiority. They're just words to me. As I said, when available, post a link to the results of the FE engines that were tested all at the same time same place and the exact amount of its superiority. You can get every engine expert in the world to post here, but I want to see the proof at it relates to FE blocks. Not Chevy small blocks or 440 Mopars. I want real world data. And I want to see it.

A few years ago, Jay Brown published a nice book called the FE Intake Comparo or something like that. I bought that book. So, a nice book with all the data proving the point (cast iron vs. alloy) would be fanatastic.

Also, if the result is 15-30 HP difference then I'd argue "WTF" that's it? All this chatter for a statistically insignificant amount of HP? I'd assert HP would/should be eliminated as a benefit or positive when choosing a cast iron block over alloy.

Honestly, we have maybe a dozen owners here of alloy blocks that don't have any reliability issues and assuming the extra HP is 15-30, which to me is insignificant, then the only reasons you would chose a cast iron block is: a) price, b) you want your Cobra replica to have a vintage block, maybe correctly dated, for "originality" purposes, ridiculous and nonsensical as that concept may be and c) the desire to add 125 lbs for no apparent reason. **):D:p

Hey RK

I'll play, I'm bored to.

1) 15-30hp is about as insignificant as the 5% weight difference you claim, no?:p
I mean maths is maths, yes?

2) Reliability was never the issue as far as the builders were concerned. Finding quality castings was, as was the risk the builder took on parts of varying quality.

3) Just to continue your rule of threes from earlier in the thread. The "chatter" you refer to in this thread is mostly you and I, and last I checked we both were happy with our alloy blocks. ;)


Enjoy...

Maybe I missed it after 14 pages of blather, but I thought the cast iron blocks were a fair amount easier to find. That being the case, if you have more than about $200 in the smoothing and powder coating, I'm thinking you might want to think twice about driving a Cobra at all.

Let's see...95% of the people can't tell an original from a replica. 99% couldn't tell you a FE engine from probably a 460. 99.5% couldn't point out a SO from a 428. How many of you race you car where the 150 lbs. will maybe make a difference?

I do.

Not Chevy small blocks or 440 Mopars.
 

Ok I have a soft spot in my heart for anal people who want empirical data for proof. I tend to be that way myself.

I did a google search yesterday to see if I could find that proof and failed. However I did find Chevy builders and Mopar guys saying that aluminum blocks make less power than iron blocks.

However I am surprised that you would not accept a test of identical parts in both blocks ran the same day on the same dyno at the same conditions, if the engine was anything other than an FE. Aluminum and cast iron do not care what shape they are cast into! They behave a certain way period. At this point you lost me. This is starting to sound like a real one argument. I didn't say that to PI$$ you off. I seriously want you step back and think about this. I'm not trying to make an enemy. I enjoy most of your posts. I apologize if I did this wrong.

At first thought, I assumed the reason aluminum blocks made less power was thermal conductivity. Aluminum will transfer heat away at a much higher rate than cast iron. Then after thinking about it, these are sleeved engines and the cylinder wall is typically ductile iron or some other iron. So thermal conductivity is not it, but it does matter on heads.

Seal issues is what I have read. If true then a sleeved cast iron engine may have similar issues. I honestly do not understand why this may be, but I do not question the observation made by so wide a group of engine builders.

I think Brent's reply should be:
So you want to spend $2500 to loose 125 lb and consider the 30 Hp loss insignificant. At a 4:1 weight to Hp ratio a 30 Hp loss is equivalent to a 120 lb gain in weight. So your willing to spend $2500 for an overal gain of 5 less pounds to accelerate? I could use a good laxative the night before a race to achieve the same results.

I have to be honest:
The smart ass comment above was to make a comical point. Without the emoticons, it looks like I'm piling on. The point is true if drag racing. In the twisty turns, the hole 125 lb matters and you cannot apply much power in a corner. However accelerating away we're back to the 5 less pounds to accelerate thing.

There is 1 valid reason so far! Good deal!

I think that says it all. We should let the horse limp away now that the flogging has ended.

If I recall correctly the original question was in reference to obtaining and preparing an aluminum block for a basically trouble free life in that; the amount of additional preparation in getting an aluminum block to that level took a significant amount of time, $ and more of a liability for the engine builder or locating one with a good core to start from. Also stated a cast iron block alleviated some of that risk.

With that being said, the question was around what is the allure from the customer's perspective based knowing this? For me it all boiled down to preference based on the Cobra build desired, i.e., $, reliability and the ease at which the car can be assembled. In my 35 years of working on cars, foreign or domestic nothing fits together better than OEM…don't care what anyone says.

If I were building an all-aluminum "hot rodded" Kirkham I would not go with a cast-iron block. I'll never quite understand the attraction but again personal opinion. A Kirkham or CSX following the originality theme, e.g. like a David Wagner build I would not utilize an aluminum block personally. Again, for other Cobra builds if cost isn't an issue would go with aluminum and some I would not. I would not however spend thousands of dollars to save 100 plus pounds or bragging rights. IMO depending on the build “theme” will determine what brings a higher value long-term so I would not say aluminum or cast-iron brings higher resale value as blanket statement.

Very true that comparable data speaks for itself but there are always other variables to consider. Then again there is no substitute for experienced passionate engine builder’s perspective.

Oh Dimis, :)

1. I could re-jet and tune my carb on a chassis dyno and get 15-30 HP. Where would I drop 125lbs with my Kirkham?

2. Yea, reliability is/was a concern. Somewhere in the last 15 or so pages somebody (not me) mentioned "power, reliability and quality." That wasn't me. And the other complaint was the alloy block casting was flexing, expanding, contracting and popping at the seams, whereas the cast iron block was rock steady and never leaks.

3. My rule of threes? I think it was Patrick and others talking in threes. I was only pointing out the anomaly. :LOL:

Pond prices his alloy and cast iron blocks exactly the same. From memory, BBM charges $1,000 more for an alloy block. At the time, my Shelby block was $1,000 extra. But Shelby has probably priced themselves out of my engine build, if I were in the market today.

And as I said earlier, I can compensate for the alleged loss of 15-30 HP in the engine build or even a chassis dyno tune. It's awfully difficult to lose 125 lbs from my Kirkham. And it's not an either/or proposition for me. I want both, the reduced weight and the extra HP from the build and the chassis dyno tune.

This has been a great thread. Like back in the old days when Keith and Cracker had some epic throw downs! Fun, fun!

I did an aluminum block because it is WAY cool. And since I built it myself, the reliability and liability is all on me. (It's been perfect, thank you very much). And getting it in and out of my basement was dramatically easier! Hell, I lifted the bare block onto the engine stand myself. Not happening with iron. Uh uh. No way.

Phil

I think I have found the reason that Brent needs to consider. If he starts a trend and all engine builders finally say enough with the aluminum FE crap I quit, this will be a disaster.

First disclosure:
I would love to have an all aluminum 482 FE in a Kirkham. In fact I would trade being able to sleep with any super model I wanted every night the rest of my life, for one. Truth is I cannot afford either. After some reflection: I couldn't handle either of them, but I can dream.

2nd disclosure:
I set a bottle of beer at each chair at my dinning room table. Then I took turns changing chairs and arguing for which engine I would put in a Cobra. At one chair a 427 SO. Another was for a Stroked Windsor. I especially enjoyed the 428 Clevor chair. You get the picture. I ended up crawling to bed and never did come to a consensus.

But here is the reason the aluminum FE must live on at all costs. In every FE verse a small block argument thread, when the small block proponents point out the superior handling on paper that their lighter engine wins hands down, the FE boys always come back with "I can build and aluminum FE that is lighter than your puny small block." If the aluminum FE becomes extinct, some one may actually win one of these useless pi$$ing matches ending the entertainment for ever.

Now that is pure logic. Hard to argue against that, well maybe a fool would.

Glad you are still talking to me.

You are correct, for what you have and do you need the aluminum FE. However, for most of the Cobra owners I have met at the London car show, I think Brent is also correct in that they really do not have a need for an aluminum FE. Unfortunately for Brent most people do not understand the difference between a need and a want.