440 source heads on a stock 440

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hemichuck

hemichuck

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I have a stock 440 short block thats been freshened up and balanced but it just has the cast low compression pistons, I dont have any heads that are done and was considering buying the 440 source stealth heads to use on it because they are closed chamber and everything would be brand new. I'm not sure if it would do much to bump the compression but I was wondering if anyone has run these heads in a similar situation and if they had good results.I have a new hydraulic cam thats 480 lift and 299 duration I think it was like 236 @ .050, is that too much duration for a motor with lower compression?
 
Just looking at the comp. ratio calculator and it came out to 8.175 with the 80 cc head and pistons .100 in the hole with .042 head gasket
 
I think that cam you mentioned is too big. It won't be great at lower rpms. It'll run, just not great. You could advance it for more torque but that's a band-aid for a poor combination of parts.

I was gonna do a similar thing with the 400 in my truck. I looked hard at those heads but decided it wasn't worth the cost. I have a lo-po factory short block with the pistons a mile down in the hole and 452 open chamber heads. The guy I bought the truck from put a .484 purple cam in it, Performer RPM and Holley 750. The combo was poorly thought out, makes very little torque at low RPM which is exactly the opposite of what the truck needs with the NP435 truck trans and a 3.23 gear. Aluminum heads would have done nothing to help it. I got a milder cam and a regular Performer intake for it but have yet to install them.

You could use the .020" shim gaskets to bump the compression up a tad but you're still going to be under 9.0:1.

When you look at cam specs, the cam companies will usually give an optimal combo for the cam, like "minimum 9.0 C.R. , 3.23 gears, dual exhaust, 750 carb" etc. The key in this case is obviously to look at the compression ratio recommendation for the cam and see if it fits.

Maybe look for another cam that makes more torque at lower rpm and can be used with lower compression instead of the heads. You need pistons more than heads but that's a whole new short block. No easy answer.
 
In the hole is never a good thing. Take the engine apart and have the block decked so the pistons are within .020" of the deck.

I have done this many times, to many 440's. The last one I did I cut the block .110" and keep the piston .020" in the hole.

This will wake up the engine and it allows the intake to sit higher up on the heads, so the roof on the cylinder heads can be raised a

little and gives a real nice alignment with the intake port roof. This modification really makes a stock short block come alive.

Tom
 
PROSTOCKTOM said:
In the hole is never a good thing. Take the engine apart and have the block decked so the pistons are within .020" of the deck.
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He needs pistons more than anything, the slugs are down in the hole .100". Decking the block .060" to get it to within .020" of the deck is not the answer and probably not even physically possible.
If you are taking the rotating assembly out and decking the block then you're buying different pistons, case closed. He does not want to take the short block apart, just wants to see if smaller chamber heads will help performance. I maintain heads won't do much in this case, aluminum or otherwise.

He would be better off with a milder cam which does not require re-doing the whole short block. He can keep the lo-po pistons but could see an increase in cylinder pressure with shorter duration, like a step or two up from an RV cam.
 
This is ForABodiesOnly so I'm guessing we are not talking about a truck here. What are you going to use the engine for? Gear ratio? Converter? The heads will make a big difference over stock iron and the cam will make considerable horsepower over stock.
 
IQ52 said:
This is ForABodiesOnly so I'm guessing we are not talking about a truck here. What are you going to use the engine for? Gear ratio? Converter? The heads will make a big difference over stock iron and the cam will make considerable horsepower over stock.
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An engine does not care what vehicle it's in. Could be in a boat or a motorhome, the same principles still apply.

Think about what is being said - you want the guy to take apart his freshly-rebuilt short block to deck it 1/16" while keeping the stock low compression pistons in it. Then, put aluminum heads on. If that is the answer you want to go with, then go for it.

If it were me, I would stick with what I had for now and change the cam, it will be a more cost-effective solution until you can build a proper short block to utilize the heads to their fullest potential. It's not going to be a high rpm street bruiser. It never will be, the foundation is not good enough to support it. But, you can build it for low rpm torque and fry the tires at will if you choose the right cam for the application.

Again, a cam will not require taking the whole rotating assembly apart. Any cam company will do a custom grind for you for little or nothing over what they normally charge, they can tailor the valve events for the combo.

I've been down this road myself. If you want any real performance, the best answer is to get good pistons then build around that. Anything else is pissing in the wind.
 
I don't recall telling him to take apart or deck his engine. He's got a fresh low compression rebuild, good enough. I maintain the heads will make a big difference and you disagree, I'm okay with that. As to the cam, I'm all in favor of using the parts you already own, so if the cam fits the engine application, use it. That is why I asked about the engine usage, gears and torque converter.

Your suggestions are fine.

Here is my experience putting heads and camshaft in a low compression 440 (what he asked about). The Stealth heads should be better than the heads I used. I don't recommend my cam for a low compression engine, but it's what I had laying around.

Dyno testing a stock(?) 1972 440
 
IQ52 said:
I don't recall telling him to take apart or deck his engine. He's got a fresh low compression rebuild, good enough. I maintain the heads will make a big difference and you disagree, I'm okay with that. As to the cam, I'm all in favor of using the parts you already own, so if the cam fits the engine application, use it. That is why I asked about the engine usage, gears and torque converter.

Your suggestions are fine.

Here is my experience putting heads and camshaft in a low compression 440 (what he asked about). The Stealth heads should be better than the heads I used. I don't recommend my cam for a low compression engine, but it's what I had laying around.

Dyno testing a stock(?) 1972 440
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Sorry, I got your reply mixed up with the first guy, don't mean to be contentious.

I guess the thing about the heads is that they are essentially copies of what he has already with a slightly smaller chamber. It's my understanding also that aluminum will not keep as much heat in the chamber as cast iron. based on those assertions, the benefits of Stealth heads in this particular combo would be marginal at best and could almost be counterproductive.

If we re talking bang for the buck, a cam that would increase cylinder pressure more than what he has now would be a better choice. There is too much overlap in the larger cam and it will bleed off cylinder pressure, like the experts always say.

I agree the heads and cam would generally be a better choice over the ancient boat anchors but in this case, it may not provide the best results per dollar spent.
 
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Stealth heads flow significantly better than stock heads in moderate lift ranges. Any decrease in chamber volume is also a benefit as well as the aluminum head increasing cooling efficiency allowing aggressive timing curves. Get a mild cam with short duration and the better head design will improve power full range.
 
I respect other's opinions. Here are mine and the reasons why.

I think he said he doesn't have any heads. Stealth heads OOTB will out flow any stock iron head buy 30-40 cfm in his lift range. Factory iron @ .400" lift, 210-220 cfm and Stealth @ .400" lift, 240-250 cfm. These numbers came off the same flowbench.

And as to the iron versus aluminum debate, I present these dyno tests.

Comparing Aluminum And Iron Cylinder Heads - Car Craft Magazine

Iron vs. Alloy Engine Heads - Tech Article - Chevy High Performance Magazine

Please note that in one of tests the testers found their suppositions (iron will make more horsepower over aluminum at the same compression ratio because of aluminum's heat transfer rate) to be in error and still denied their own test results! In both cases the aluminum heads made more power. Old wife's, er, mechanic's tales die hard.
 
I think Stealths are a good fit here. Just have a shop check them out before you bolt them on and I would replace the retainers and locks, or go for the upgrade when you order them. In regard to compression - I really don't think it will matter much. It's one thing if it's a yet-to-be-built engine but if something's done there's not much reason to re-do given the mild mannering it will have given the camshaft noted. I ran a cam 10° larger at .050 in a '76 used factory short block many years ago in a heavy E body. Drove it daily for two years: cold, snow, heat, pump fuel... Ran low 12s on GT Qualifiers. With a better head that engine will be stout.
 
Its actually going in a 1966 Belvedere 4 door and probably wont see a lot of performance use. I will probably just get rid of that cam and go with one of the smaller RV style cams. I know that the Mopar performance 430 lift cams made a ton of low end in motors with low compression so I might hunt one of those down. Do you think in such a low performance package that there is any advantage at all with the stealth heads or should I just dig out an old set of 906's and have them reworked?
 
hemichuck said:
Its actually going in a 1966 Belvedere 4 door and probably wont see a lot of performance use. I will probably just get rid of that cam and go with one of the smaller RV style cams. I know that the Mopar performance 430 lift cams made a ton of low end in motors with low compression so I might hunt one of those down. Do you think in such a low performance package that there is any advantage at all with the stealth heads or should I just dig out an old set of 906's and have them reworked?
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Though it seems to be against popular opinion, I would say there is no advantage to those heads in your situation, other than they are new. That's the thing that almost swayed me into buying those heads - the idea of sinking money into 45 year old open chamber iron heads to 'fix them up' or somehow optimize them was not very appealing. It's a tough pill to swallow when you have the Stealth heads staring you in the face for just over a grand. But, I resisted.

A cam with less duration will be a better choice. 236 @ .050" is not huge but it's not small either. 299 degrees of total duration is way more than needed.

Again, the one thing above all else that would make the biggest difference here is pistons, not heads. If you had the compression to take advantage of good flowing heads and were planning on making some power, then yeah, go for it. To me, it sounds like a cruiser with a little more oomph, like a police interceptor type thing.
 
My Daddy, who built engines for NASCAR, told me there were three main secrets to making horsepower. The first two secrets were cylinder heads, and third and most important was cylinder heads. If you have a 7.5:1 compression engine making 350 horsepower and you change the cylinder head flow from 220 cfm to 250 cfm you will gain about 50-60 horsepower. That is why I posted the low compression 440 dyno test, that is what we saw when we changed the heads. On the same engine, if you raise the compression 2 full points, how much horsepower gain can you expect? Maybe 23 horsepower?

The Power Squeeze
 
I would not worry excessively about compression at the moment, put good heads on it and go with less duration on the cam. And you can use 87 octane pump swill. Using a .904 lifter, you should be more like .525 lift at 235 degrees @.050

The stealth's make more sense than putting money into iron heads, unless you can do the work yourself or get it inexpensively. S/F....Ken M
 
Today at 8:14 AM#6

rmchrgrSkate And Destroy
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Decking the block .060" to get it to within .020" of the deck is not the answer and probably not even physically possible.

You have no idea what your talking about. It is physically possible and done to many race engines.

Decking the block and raising up the port roof will do far more than just sticking in a set of pistons.

From now on I wont waste my time telling how you can get one to run really well for little money and a few extra hours of work.

Tom
 
Dang it Tom you are getting as grumpy as Rusty! So some of us only know "amost" everything!:rofl:

How much is it off the intake when you deck 0.060?
 
mguner said:
Dang it Tom you are getting as grumpy as Rusty! So some of us only know "amost" everything!:rofl:

How much is it off the intake when you deck 0.060?
Click to expand...

About 0.0738", you know, approximately, + or - 0.0004562"
 
I don't cut anything off the intake. You have to elongate the intake bolt holes a small amount, but you cut nothing off of it.

This makes the intake sit higher up on the heads because the deck height is now lower.

There is always a misalignment were in the port roofs of the intake with most all combinations even if you port match,

your still not getting a nice straight transitionless roof.


Doing what I am talking about allows you to straighten the ports in the head and the intake out and have a very straight

smooth roof instead of being curved down like intakes and heads are at the opening. It takes some time and effort, but by

doing what I do I can get a 9.5 to 10 compression short block using stock pistons that were way down the hole to start with.

I have been building engines and racing for 36 years, so I have learned a thing or two about how to make power.

This might sound like a unorthodox or foreign idea to most people, but if you really understand how to get a lot out of an engine

then you will understand the logic in what I am talking about.

Tom
 
Thanks Tom, the logic wasn't lost on me, as a matter of fact the same thing was suggested by one of my friends who builds engines
 
Seems like a lot of work for this combo, and IMO the butcher's way of doing it unless for some reason you're class-restricted to using specific parts and really have no money. Not saying it can't be done that way or that the direction Tom is referring to would not pay dividends, but I wouldn't do it. Go with Stealths and avoid this nonsense.
 
This post is more or less a case of me trying to use up stuff I've had laying around for a long time but in the long run I think the best and most satisfactory outcome can be achieved by me taking all this stuff to a swap meet and cutting it loose and just buying what I need.
 
hemichuck said:
This post is more or less a case of me trying to use up stuff I've had laying around for a long time but in the long run I think the best and most satisfactory outcome can be achieved by me taking all this stuff to a swap meet and cutting it loose and just buying what I need.
Click to expand...

X2. More of a hassle than it's worth, as evidenced by this thread.
 
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