Aluminum Heads, Engine Build

[tricky lugnuts]

Have some questions and looking for feedback on a 440 engine build.

* Aside from the extra cost, is there any reason in terms of durability or performance NOT to use an aftermarket aluminum cylinder head (say, Edelbrock or Stealth head), as opposed to a stock cast iron head, on a 440 engine that will see mostly street duty, upwards of 5,000 to 10,000 miles a year, and maybe some track time two or three times a year?

I'm looking to replace a set of cast iron 346 heads with some burnt up exhaust valves and, with the cost of rebuilding those rapidly approaching the $500 mark, I'm considering spending a couple hundred dollars more to buy a set of Stealth heads.

I've read all the threads on this site and on Moparts, or at least most of them, and read about the questionable locks and retainers on the Stealth heads ( I plan to upgrade those), and getting the out-of-the-box machining checked out.

* But are there are any other potential downsides I may experience with a switch to aluminum heads - particularly in terms of corrosion, warping, those kinds of issues?

I need the engine to be durable and reliable and would like it to perform at least a little better than stock without having to swap head gaskets every 10,000 miles or buy a new set of heads any time soon.

* I know, there are no guarantees, especially from you guys, and that you get what you pay for, but are there any inherent aspects of an aluminum cylinder head that make it a questionable replacement part for my application?

To that improved performance end, I also plan on buying an Edelbrock Performer intake and a 750 cfm Edelbrock Performer or 800 cfm Edelbrock AVS carburetor.

I know the Edelbrock carbs are not the most popular, with some people recommending Proform carbs and others recommending Holley carbs, but I'm already used to the old AFB design and I know how to work on it and tune it and want to stay with something like that for right now.

I decided against going with the popular Performer RPM intake because of hood clearance issues (1971 Charger with a flat hood) and also because I don't plan on my engine running any higher than 5,500 RPM at this point. I want low end torque and tight throttle response, and it seems like the Performer is more suited to my intended application, the idle to 5,500 RPM range.

The bottom end of the engine is all stock 1971 stuff in terms of crank and pistons and deck height.

* Will that stocker bottom end pose a significant problem with simply bolting on the stealth heads right now in terms of performance and compression ratio, with the pistons not at zero deck height?

I'd prefer to not mill all the meat off the stealth heads right away, only to wish I had that material back when I have the short block redone later this year and can have pistons set closer to zero deck.

* With stealth heads, a Performer intake, a 750 or 800 cfm carb, stock torque converter and 3.23 gears - and a conservative cam, either a stock 440 Magnum replacement or a Comp 268 or something like that, can anyone offer any guesses in terms of what I'll see performance-wise? Any suggested improvements to this approach?

I'm looking to build a reliable 440 engine that will perform better than stock, pull good vacuum for the power brakes, and get decent fuel economy for a big-block Mopar - something comparable but slightly less than the Car Craft 440 build in the proven combos section.

I'm hoping the close to 100 pounds in weight savings from the aluminum alone will help in terms of handling and acceleration, but I just want to make certain it's not unreasonable to expect those aluminum parts to hold up on something that could see some grocery-getter, cross-country hauler duty before I spend the coin on any of the parts, and that the build makes sense in terms of matched components.

Thanks for any and all help!

[1Bad70Charger]

Do it once and do it right get the Eddy Alum. heads they are simply a better product than the 440 source heads and no, their is no downside to doing this and this is what  you want to do for your build up you describe.

You can do the 440 source heads to of course but MUST upgrade the locks and retainers, etc. but my research has show that the Eddy Heads are simply a better product and  you usually get what you pay for!  

If I keep my current 440 in my 60 Roadrunner for another year or two, before upgrading to a Hemi or a 650 hp stroker 440, I will be upgrading from my iron stock heads to the Eddy alum heads as they just can't be beat when it comes to performance, quality and pricing!  

[Challenger340]

I'll give a second vote for the Eddy's Heads better "useability" straight out of the Box over the Stealths,
however,
IMO, they should be checked over prior to use as well.

As for any problems with Longevity on the Aluminum Heads, NO, they will provide excellent service life even in Daily driver applications.

Specific to YOUR Engine application, IMO, I don't think you have enough Compression Ratio for any, or much, of a Performance gain, even with the 268H Cam.

The Aluminum will effectively decrease the applied Compression, due to the heat Dissaption characteristics of Aluminum, even though the static C.R. should go UP slightly with a smaller Chamber, NET LOSS.
That,
coupled with more Duration from the Cam, will probably amount to even less "snap & response" at lower rpm's, but BETTER mid-range and top end with the better Head Flow & Cam once it gets going.

You mentioned 5500 rpm max, so not much "overall gain" when losing down low ?

IMO,
The biggest dis-appointments when going to Aluminum Heads for Performance gains, is applications with Lower Compression Ratios, where unfortunately you are.
It'll run fine,
you may see some "gain", but I do not think it will be a dramatic increase. 

[firefighter3931]

Another vote for the Edelbrock closed chamber RPM's. 

When you pull the heads do a piston to deck measurement and then it'll be easy to calculate the static compression ratio. 


Ron

[tricky lugnuts]

Thanks for the feedback!

I hear you about the Edelbrock heads being a better choice, but this is a tight budget build, and the $400 or so hopefully saved with the Stealth heads will be used to buy the carburetor and maybe even some of the intake manifold.

It ain't easy building a Mopar on my wages and at this point every dollar saved adds up!!!

Thanks for the feedback on the durability of the aluminum heads in terms of a daily driver application. A friend that I respect had suggested that he likes aluminum heads for race builds, if anything, but not for a daily driver application like mine, so I just wanted a couple more opinions on the matter.

As far as the compression ratio goes - it looks like the flat-top replacement pistons sold by 440 source sit .018 inches down in the cylinder. I assume that's comparable to the stock flat-top pistons I'm running. Assuming an 80cc Stealth head, it looks that would put the compression ratio somewhere around a high 9 to 1 or low 10 to 1 without factoring in the head gasket, which would further lower the ratio.

In terms of measuring how far my pistons are down, I'm really challenged right now in terms of tools. I've been doing all this in a gravel lot outside my apartment. Kind of sucks, but it's what I got. Should I just try and get some kind of feeler gauge set and measure as close as I can?

* It looks like 440 Source offers two head gaskets, the white ones with a compressed height of .051 or the blue Fel-Pros with a compressed height of .039 inches. I'm assuming, with my lower compression ratio engine, and my pistons down in the cylinder, that I should use the thinner blue Fel-Pro gasket to bump the compression ratio up a bit in the short term.

So if I understand you correctly, it sounds like just bolting on the Stealth heads will give me a slightly lower than desired compression ratio for using aluminum heads, given the stock pistons and stock rods, but that the compression ratio will be high enough to work and likely be a wash performance wise for now, compared to the stock 346 heads.

But if I'm understanding everything that I've read, when I go to build the short block later this winter or early next spring, I could have the engine block machined to put the pistons closer to zero deck height and bump that compression ratio up to around 10.5 to 1, which would be ideal for the aluminum head. That or else mill some off the bottom of the Stealth heads. Correct?

Just so we're clear, that's what I intend to do in the future if that's what would work best - either get the pistons closer to zero deck by cutting the block or else milling some off the heads if I have to.

Also, I intend to install the new cam when I build the short block at a later point in time, so for now I'll be stuck using the stock 1971 440 cam. Will that stock cam change anything in the short term, in terms of being able to use the Stealth heads and the performance level?

Assuming this combo I've outlined, would there be a better cam to use than the Comp 268 cam when I build the short block? I'm a rookie at all this and plan to work with the engine builder when I get to that point, but I just want to gather input and advice to be better prepared. Thanks again for any and all feedback.