Gain from Stock 452s to OOTB Stealths?

[Budnicks]

RPM's too

our Stealth heads use factory type rocker arms and stock diameter shafts, so no special "high-dollar" offset rockers are required. Any rockers that work on a stock Mopar head will work on our heads. This includes roller rockers, or even stock type stamped steel rockers. Heat crossover is blocked off for increased performance. Factory port windows, exhaust and intake manifold locations make sure you can use any "off the shelf" intake manifold and/or exhaust manifold/headers without any fitment hassles or special "spacers" required.

Just for general information.... The RPM's, MP, some Indy & other aftermarket aluminum & cast iron heads, especially in the smaller std. port configurations, use the stock size/type, shafts, valve-train & rockers, but your right some heads need, the high dollar offset rockers &/or special stands, springs,locks retainers, seals, long valves & such... forewarning; {with 3/8" push-rods, not sure with 5/16" push-rods} With the Stealths if you go more than a 1.5:1 rocker ratio, you need to grind quite a bit of material, on the outside of the intake ports casting for push-rod interference clearances, "I've been there done that"... Even using 3/8" push-rods, I have run 1.6:1 ratio Super Gold Crane rollers & 1.6:1 Harlen Sharpe rollers & Isky ductile iron M/W type 1.6:1 rockers on Edelbrock RPM's @ near 0.600" gross valve lift, with no grinding for push rod clearances or special offset rockers.... with no fitment hassles, even with the RPM's superior angle plug design, fitment isn't really a issue, many stock 68-70 383/440HP type cast iron manifold, Super Stock CI manifolds & many other 1-7/8" & 2" headers, all fit with no fitment issues on any I've used, TTI, Schumacher Creative Services, Heddman, even some Hooker's, I have heard some people complain about plug wire clearances though, but usually it was on some of the cheapo brand/style of headers...

 

[67Satty]

I found this on the Hughes Engines website located here (http://www.hughesengines.com/TechArticles/7choosingheadsaluminumvsironwhichonesdoyouneed.php):

"All "stock replacement" performance aluminum heads are designed to develop more power than the iron heads they are replacing. However the gap between what was designed and what leaves the factory can be worlds apart.

When aluminum heads are cast there is a lot of core shift, more than with iron heads. That core shift ALWAYS reduces the air flow in the port. The question is how much flow is lost and is it significant in reaching your goal. We constantly check the "out-of-the-box" flow of heads that we are porting and find them to be down 15 to 30 CFM. The CFM from port-to-port will also vary 15 to 30 CFM in the same head (please refer the our Flow Bench section for further information).

In an effort to reduce manufacturing costs on ready-to-bolt-on heads, "finished" seat rings may be installed in the heads by pressing or driving. This procedure causes the seats to go out-of-round. We have seen them out-of-round 0.014" to 0.016". The limit should be 0.002" or less. Seats this far out of tolerance will cause hard starting, rough idle, and reduced power output. Originally, performance aluminum heads were designed for porting shops to finish and correct the manufacturing flaws before the head was installed. That way the problems of core shift and out-of-round seats never reached the end user.

Aluminum heads will not automatically create more power than iron heads unless they flow more air and are installed on a higher compression ratio engine. In cases where you have a decent port job on a set of iron heads it is possible to bolt on a set of out-of-the box aluminum heads and lose power. Aluminum is automatically lighter but not faster.

Quick Facts: Aluminum vs Iron

Weight: Aluminum heads weigh about 45 to 50 lbs., a pair, less than iron heads
Durability: "Ported iron heads can crack if the engine is badly over-heated". Yes this is true, but if the engine got that hot the aluminum head would have melted or been badly warped. The seat rings would have also fallen out, but the head might not crack. Anyone who lets his engine get that hot deserves to buy new heads or have an expensive repair bill
Reparability: This is a trick question. Yes, aluminum heads are easier to repair if the damage is very bad and that is a good thing because they are much more fragile and more prone to damage than a hard, iron head
Cost: Aluminum heads cost more, and then there may be the hidden cost of raising the compression ratio
Airflow: You get very similar airflow results from ported, stock heads and "stock replacement" type heads. With raised port cylinder heads, the sky is the limit
Power: Power depends on what you have to start with, or what else you plan to do to the engine. If you have low compression (9.5:1 or less) and are not going to change pistons or mill the heads to restore the cylinder pressure, save some money and go with the ported iron heads. If you are starting on a fresh engine with higher compression ratio pistons, want to lose some weight and the budget can handle it ---go ported aluminum. There is another power consideration; most of the aluminum heads have a closed combustion chamber which is far superior to the OEM heads with their open chamber design. However, if the piston is not at 0.000" deck, the chamber design has very little effect."

The parts that I bolded are the parts that I'm curious about, again just throwing this up for discussion to those who know much more than me and have the resources to have played around with this stuff much more than me. Thanks!

 

[67Satty]

Just got off the phone with a tech guy at Edelbrock. I was asking about the difference between the Edelbrock RPMs and the E-Streets due to come out at the end of July.

Here is what he told me:

Both are the same exact casting.

The RPM has hand blending and bowl work that the E Street does not have.

The RPM intake flows 292 at .600 lift, the E Street intake flows 291 at .600 lift.

The RPM exhaust flows 217 at .600 lift, the E Street flows 217 at .600 lift.

He said the lower lift numbers are also very close.

I forgot to ask him if the E Street has a straight plug.

The E Street uses heavier valves and retainers.

The aren't recommending the E Street for people wanting to spin past 5500.

 

[Budnicks]

67Satty that is the same thing the Edelbrock engineer said to me, that is what I posted earlier too... I-M-H-O Most of that is, just BS & an up-sale, trying to sound like the "be all end all experts", yes there can be some very nominal core shift & flow differences, but the basic CNC macining, before shipping & better quality control {at least in the American mfgr. companies, some of the foreign stuff is really bad} has stopped most all of that stuff... Most of the time the differences between Cast Iron in relationship to compression is "nominal at best", from Cast Iron being superior to "another identically ported/equipped Aluminum head" {especially if it has a smaller CC combustion chamber}, your talking about maybe in true reality 2-3 HP max & 2-3 Ft-Lbs of TQ max, in a DYNO Cell, something the "lighter weight difference alone", will more than make up for the HP/TQ difference in overall performance, more than the nominal HP difference between the 2 types materials of the heads, especially on lower compression engines in heavy cars, but as always, opinions will vary vastly, as they often do... Just do your research, you can find all kinds of stuff about "any engine builder", especially the, workmanship quality, parts quality, shipping rip-offs, refunds for wrong or bad quality parts, bad materials, plus many warranty type issues & bad reputations, it spreads much faster than any of the good reputations, if you search well enough, especially on the Many Mopar Forums available nowdays... Remember performance is all about, "the power to weight ratio", how much it takes to move any given weight....

 

[Sweet5ltr]

I went with the Edelbrock Performer RPM's like many have stated above. My father and myself, bolted them up "right out of the box" and absolutely no issues have occurred. If you check the pricing on the Stealth Aluminum heads, you may be saving $300-$400. What you must look at are "out-of-the-box" flow numbers. The Stealths have been very INCONSISTENT with their flow rates, and some are barely clearing more than 260cfm at .600 lift on the intake side. I don't know about you, but I am not paying for my NEW cylinder heads, to be cleaned and ported to meet the advertised flow rates. Beyond that, the parts are inferior (were inferior) that are initially installed. Last but not least, you are buying from a company without a 'good' reputation due to quality issues and supporting CHINESE WORKERS!

If anyone is in the mindset that a BB Mopar "Cast Iron (452, 906, etc.) Cylinder Head can out-perform a modern aluminum casting then they need to get their head examined. MAJOR, PROFESSIONAL Porting is required to get the flow rates of some of the modern cylinder heads available on the market. The weight alone is worth the change over. Power-to-Weight ratio is dominant in racing. The dropped weight will also give you better weight distribution for cornering, braking, and hooking up at the strip!

It all depends on combination, and camshaft selection. I went with a moderate grind from Comp Cams. Not ready to go to .590+ solid lifter in an everyday driver. Their isn't any need to put that much stress on the valve train. I went with the Victor 440 single plane to get the most out of the combination as well. The cylinder heads can make or break your performance, so I would not skimp out and do something I would regret later on; like spending loads of money on cast iron heads! Just my opinion, hope you make the right choice!

 

[67Satty]

Yeah, at this point I am leaning towards some aluminum heads rather than messing with my 452s. Even if someone could get them to flow as good as OOTB aluminum heads they would still weight more and not have as good a combustion chamber design.

And the part about the Stealths barely clearing 260 kind of bugs me a little too.

The thing that goes against the Edelbrocks for me is not the $500 higher price so much. It's the fact that I have Hooker 1 and 7/8 headers and I'm not sure if they will work with the Edelbrock's angled spark plugs. Anyone have any info on this for me?

If I have to buy a pair of $600 headers to use them that would be a total deal breaker for me.

 

[Sweet5ltr]

Yeah, at this point I am leaning towards some aluminum heads rather than messing with my 452s. Even if someone could get them to flow as good as OOTB aluminum heads they would still weight more and not have as good a combustion chamber design.

And the part about the Stealths barely clearing 260 kind of bugs me a little too.

The thing that goes against the Edelbrocks for me is not the $500 higher price so much. It's the fact that I have Hooker 1 and 7/8 headers and I'm not sure if they will work with the Edelbrock's angled spark plugs. Anyone have any info on this for me?

If I have to buy a pair of $600 headers to use them that would be a total deal breaker for me.

Here is a good article to refer to cylinder head flow numbers;
http://www.moparmusclemagazine.com/..._cylinder_head_testing_flow_charts/index.html

 

[Budnicks]

Thanks

Here is a good article to refer to cylinder head flow numbers;
http://www.moparmusclemagazine.com/..._cylinder_head_testing_flow_charts/index.html

That was interesting, Thanks for the link.... Maybe IQ52 will chime in on those #'s, he has a bunch of the Flow data, from all his Professional Cylinder Head Porting, building, research & testing... I wonder how they compare to MMM testing...

 

[Budnicks]

not sure

The thing that goes against the Edelbrocks for me is not the $500 higher price so much. It's the fact that I have Hooker 1 and 7/8 headers and I'm not sure if they will work with the Edelbrock's angled spark plugs. Anyone have any info on this for me?

If I have to buy a pair of $600 headers to use them that would be a total deal breaker for me.

What part #'s are the Hooker Headers you have ??, you can call them or you can go to there web-site @ www.holley.com & see if they will fit the angle plug style RPM heads, I have had Hookers on RPM's but I don't remember what part #'s, they were old crappy headers, that came with the car, I replaced with S.C.S. Headers latter, I don't own the car any longer either to check... Speed & Hp/Tq cost money, especially MOPAR's, it's an investment, do you want a quality part or some cheap piece of ****, I say, "wait & save for the proper parts & combo, get all the parts together, then install them, so you don't spend the money twice"... If you think TTI's, Doug's or Schumacher Creative Services headers or any others quality fitting headers for MOPAR's are expensive headers, just try building "real Race headers", the merge collectors alone, are nearly at or more than the total price of the Ceramic Coated TTI's, F-Y-I also none of the "out of the box, bolt on headers", are true "race headers" or even actually equally length tubing or "tuned headers", they are all just intended for street cruisers or street/strip cars, especially if they have a 3-4 bolt flange to bolt on an exhaust system... I guess it depends on what it is your doing, your budget, your expectations, etc., but if your worried about finite flow #'s in differences in cylinder heads, the same considerations, should be taken on the exhaust, it should be just as important, what goes in, must come out... I wouldn't make a choice of cylinder heads, because of a choice of your existing exhaust, you need to match the components to, intended usage/expectations, compression, camshaft, valve train, headers, fuel & induction system, to your combo... not to fit you existing parts... I'm not saying this is you, at all, but that's a "big mistake" many, many builders make, then end up spending a bunch of extra cash, because they don't get the expected performance #'s, because of a poor combo choices or a cheap skate combo or then have to spend more now, to make it run the way it should have, to begin with, if they used the proper combo when building it the 1st time... sorry for the **** retentive exhaust rant, Have fun & Happy Moparing

 

[Sweet5ltr]

few more from various sources;

Stealth/Eddys flow numbers box stock
100 --- 65/79 --- 57/70
200 --- 135/143 --- 108/126
300 --- 191/207 --- 140/160
400 --- 227/256 --- 159/188
500 --- 242/278 --- 173/206
600 --- 254/291 --- 183/217
700 --- 261/292 --- 191/223

http://i112.photobucket.com/albums/n194/dwamboldt/other/index.jpg


I have my flow #s at work so here are the before and after @ .600:
Superflow 600 Bench @ 28" and Port Flow Analyzer 3.0 software:
Intake 254.4 Exhaust 198.3

4.375 bore, 28" test pressure, radius plate on intake, no tube on exhaust:
average flow for #5 and #7 cylinder
lift----I/E 440 source
.100--63.8/49.0
.200-140.5/104.1
.300-207.8/139.7
.400-239.2/164.6
.450-248.1/172.5
.500-256.1/177.8
.550-261.5/182.6
.600-265.3/188.2
.650-267.3/191.5
.700-267.3/195.8

 

[Moparmatt72]

Thanks for the numbers glad I ported my stealths gasket matched and blended.

 

[IQ52]

Here we go again.

It depends upon the head porter and what he designs the head to do.

http://forums.moparmusclemagazine.c...iscussion/440-source-stealth-heads/index.html

Please note the flows listed for the seriously ported Stealth heads listed on page two and on page three there are some examples of a 906 from stock to ported to 320+ cfm. We can port the 906 heads to over 340 cfm but you could buy three pair of RPM heads for the same price.

 

[Sweet5ltr]

Thanks IQ52,
I posted numbers from OOTB stealth castings, since that is exactly what the original poster is looking for. Many people do not port their own cylinder heads, but would be required to spend an ample amount of money doing so. If anything, just a large amount of time finding a quality shop! Stock for Stock, IMHO the RPM head is clearly the winner in nearly every condition and test.

 

[Moparmatt72]

Here we go again.

It depends upon the head porter and what he designs the head to do.

http://forums.moparmusclemagazine.c...iscussion/440-source-stealth-heads/index.html

Please note the flows listed for the seriously ported Stealth heads listed on page two and on page three there are some examples of a 906 from stock to ported to 320+ cfm. We can port the 906 heads to over 340 cfm but you could buy three pair of RPM heads for the same price.

I know it depends on the porting person, I'm no professional at it by all means just glad I opened mine up was all I meant by my post. I'm not sure what they are flowing due to no flow bench, just went by feel.

 

[IQ52]

Thanks IQ52,
I posted numbers from OOTB stealth castings, since that is exactly what the original poster is looking for. Many people do not port their own cylinder heads, but would be required to spend an ample amount of money doing so. If anything, just a large amount of time finding a quality shop! Stock for Stock, IMHO the RPM head is clearly the winner in nearly every condition and test.

OOTB my tests on the Steath and RPM would agree with your findings. I too believe the RPM is the better head OOTB. That is why I gave reference to the Mopar Muscle Magazine Forum with the OOTB flows for both. I am also heyoldguy there. However, to bring the Stealth up to the OOTB RPM flows is a very simple procedure.

 

[bigmanjbmopar]

I think It's time for a race. Heads to head 452 vs eddy vs stealth, you know what they say It's all in th et. Lol

 

[bigmanjbmopar]

I would like to see cars with each set up all out of the box no port work with 1.5 ratio and 9.5 or 10.1 comp close in cams etc go head to head at the track and see what happens. I mean in the end you guys all all just trying to see who has a bigger/better head right? lmao

And for the aniti china thing go look through out your home or mobile trailer and tell me that every single ting in there was made in the USA. not going to happen so get off your high horse. get over that casting doesn't matter where it's done.

 

[67Satty]

What part #'s are the Hooker Headers you have ??,

These are the Hooker 5903 Competition ones that are 1 and 7/8" that fit both B and E bodies. $600 TTIs are just not in the budget, though I see your point about speed costs money and only buying things once. I'm a low-budget guy and it's part of the fun and challenge for me to see how fast I can go for how cheap. That's way I was considering just porting my 452s - to be different and to see how fast I could go for how cheap. But now I'm leaning towards the aluminum heads.

 

[Budnicks]

These are the Hooker 5903 Competition ones that are 1 and 7/8" that fit both B and E bodies. $600 TTIs are just not in the budget, though I see your point about speed costs money and only buying things once. I'm a low-budget guy and it's part of the fun and challenge for me to see how fast I can go for how cheap. That's way I was considering just porting my 452s - to be different and to see how fast I could go for how cheap. But now I'm leaning towards the aluminum heads.

We all hav a budget we need to live by, it's not have to buy, it's just about want to buy... Good luck ,Happy Moparing, you can still make great power with the 452's...

 

[RustyRatRod]

Here we go again.

It depends upon the head porter and what he designs the head to do.

http://forums.moparmusclemagazine.c...iscussion/440-source-stealth-heads/index.html

Please note the flows listed for the seriously ported Stealth heads listed on page two and on page three there are some examples of a 906 from stock to ported to 320+ cfm. We can port the 906 heads to over 340 cfm but you could buy three pair of RPM heads for the same price.

What?? Are you over here spreadin hooha too? LOL

Hay Jim!!!