aluminium head questions

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440+6scamp

440+6scamp

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I've searched and read as much as I can about the topic but I have some specific questions about my build that I couldn't find answers for.

My car:
'74 Scamp
3400 lbs
4.10 gear
727 w/ 3000 converter
7.67 sec 1/8th mile (haven't run 1/4 but expect low 12's)
440 .030 over, 3.75 stroke
452 heads (open chamber, 88cc)
9.5 compression
hydraulic flat tappet lifters
Comp XE274H cam (.488/.491 lift, 230/236 duration)
1.6 rockers (makes lift .521/.524)
Edlebrock 6 pack intake
holley 6 pack carbs
custom built headers (1 7/8" stepped up to 2")

The main things to be gained going from 452's to AL:
-can get closed chamber vs open for 452
-about 290 cfm intake flow vs 205 or so for 452
-up to 10.5 or so CR compared to current 9.5
-lighter

What I'd like to acheive:
Gain about 50 HP while keeping the look of the 6 pack setup and still drive good on the street while running 11.60's or .70's. My car is probably 90% street driven but even when street driving I'm the type that likes to know there's a lot under the hood.

Based on my build and 1/8th mile time I think I have about 450 HP. I'd like to reach 500. I'm considering aluminium heads. Is it possible to gain 50 by just swapping out the 452 heads for aluminium? Or, would I have to ditch the 6 pack intake and carbs in place of a single plane intake and 4 barrel?

My headers are custom built and very close to everything (valve cover, torsion bars, steering column, starter, trans, spark plugs, etc) so it's imperative that any head change doesn't move the exhaust. Along w/ that, it seems like a lot of aluminium heads have angled spark plugs. I'm not sure that angled plugs will work for me.

So, is there a head that will give me 50 HP w/ the 6 pack setup and not affect my exhaust (no angled plugs)? If angled plugs are my only option, can anyone tell me how much angle they have (a referrence to the amount that the end of the plug would move would be great).

How much compression can I safely run and still have a well-mannered street car?

All suggestions are welcome. Sorry the the long read.
 
Ok, lets assume for now that the angled plugs wont work on my car. What's the best straight plug head? The only ones that I know of are the 440Source and Mopar Performance heads. I've heard mixed reviews on the Steath heads. My understanding about the Mopar heads is that they're copies of the Edelbrocks but w/ straight plugs. So, are the MP heads my best option if I need straight plugs? Are they open chamber (I know they're 84cc)? Can I expect to gain 50 HP w/ them? I'd like to get the CR up to 10.5 or so but that would take a 78cc or less chamber.

Any thoghts? Any feedback on the MP's?
 
All depends on how much money you want to spend those heads can be modified to get that kind of power the compression will for sure make a difference in how the motor responds also look at your cam if its performance you are after. 500 hp should be no problem with the right components even with the 452's but the weight savings and the compression difference will help the car a fair bit.
 
You can approach 12:1 on pump gas with aluminum heads and a well thought out quench motor. Because the aluminum heads dissipate heat so well, you can get by with a good bit more compression. Couple that with using a good closed chamber design and a properly set up quench short block and a well thought out camshaft and you might could get to 12:1 on pump premium. With that much compression on a quench motor and good flowing heads, you'd certainly eclipse 500 HP.
 
Lets forget cost for the time being. I'd really like a set of Indy heads but as far as I know, they don't make a set w/ straight plugs. Is there a closed chamber set of heads w/ straight plugs?

Going from my 452's to the MP's would only bump up my CR to 9.8 or so. I'd like to get to 10.5. Any other options?
 
I know of 3 heads that will work (stock intake and exhaust ports and straight spark plugs):

Mopar Performance part #5153524
84cc open chamber
290 cfm intake flow
2.14/1.81 valves
Mancini mentions "452" casting... is this basically an aluminium version of the 452???

Mopar Performance part # 4876311
78cc closed chamber (Summit lists it as 84cc???)
290 cfm intake?
2.14/1.81 valves
Mancini compares the flow as being better then the "906"... is this basically an aluminium version of the 906?

440Source (Stealth)
80cc closed chamber
2.14/1.81 valves
280-290 cfm intake
They also offer a CNC ported version that sounds pretty nice:

http://store.440source.com/Stealth-...s-ASSEMBLED-SINGLE-HEAD/productinfo/200-1080/

315/230 cfm (intake/exhaust) @ .600" lift sounds pretty good for non-raised intake ports

My only concern w/ the Steath heads are the few negative feedbacks I've come across. I'm not sure if the folks that have negative comments about them have actually used them or if they're against them b/c they're not a name brand.

Of these 3, I would eliminate the open chamber MP. That leaves 2 choices. Am I missing any straight plug, closed chamber heads? I sure wish Indy made one.
 
Anybody know what the Stage 6 flows? Unported and ported?
 
Go with a set of Edelbrock heads. 84cc. I had no problem getting 500Hp with these heads. With your set up and these heads you should be around 485 HP to 500 HP. Thats by my figures anyway.
 
You're gonna find negative feedback about any of them. You caint please everybody. THing is, if you keep in mind you are buying a head that you KNOW will require some finishing and or tweaking to your particular situation, you probably won't be disappointed. I've seen negative feedback about them all, but moreso the Eddys than anything else. Probably because they are the most popular.
 
from what i've seen and heard edlebrock makes the Mopar Performance heads for mopar same ports on both and same flow numbers the diffrence is the angled plugs in the eddys while the mopar run a straight plug which only comes in to play when running really high compression just my 2 cent
 
If I can find a CNC ported version of the MP heads I'll probably go for them. The off-brand, China made stigma of the Steath heads has me a little worried. However, I haven't found a ported version of the Mopar head yet. Does anyone know where I can find one?

Also, what intake/carb combo would be best for this setup? I'm partial to the looks and nostalgia of the 6 pack setup but if I'm leaving HP's on the table I'm up for a change. I think I'd perfer low end torque over high end HP.

I haven't seen exhaust flow #'s on the stage VI's but I'll keep looking.
 

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Are you aware Edelbrock's stuff is also outsourced? It is. He can claim his stuff is "made in USA" as long as a certain percentage of his products are made here.
 
Good point. The #'s and price of the ported Steaths are hard to pass up. And after all, I'm not building an all out race motor... just a strong street motor.

How bout the induction? Am I giving up more then 10 HP there?
 
Now I'm not so sure... I'm finding a lot of posts like this:

http://www.cuda-challenger.com/cc/index.php?topic=52902.0

I know that's just a few folks opinions but the exposed gasket and dropping valve issues seem to be repeated on several forums.

So, back to the MP heads. Everyone claims the "452" head (5153524) is the same thing as the Edelbrock RPM (in fact made by Edelbrock w/ a Mopar logo) but w/ straight plugs.

What about the MP 4876311? I can't seem to find any feedback about it. I would think it's a better choice since it has a smaller, closed chamber. Do people not prefer the factory 906's over the 452's for the combustion chamber? Why is so much made of the "452" Edelbrock copy head but so little mentioned about the "906" 4876311 head?
 
Unless you or someone you know is a wizzard at multiple carburetors, you're leavin horsepower on the table. Multiple carburetion is always better than single.......IF and ONLY if they are in synch and tuned correctly. This is why over 90% of the time you see single carbs winning out. It's almost a lost art in a way. Probably one of them new Holley 870 vacuum carburetores would be good on top of sumthin like maybe an air gap.
 
Here's are Eddy's 440 pump gas street car.
11.1-1 comp

IMGP0230.jpg

Runs's 10.70's on soft tune off the juice.

This car had 906 heads ran a best of 12.21 off the juice.
IMGP0513.jpg


Changed to stage IV heads.
Ran 11.70's first pass off the juice.
IMGP1289.jpg
 
Thanks for the #'s womanator. That's the kind of gain I'd like to make. I'm not familiar w/ the specs on stage IV heads. How do they compare to the "452" and "906" MP heads?
 
All these heads are ported but not full race ported.
The iron heads are 452.
They flow 79% compared to the Eddy heads.
The stage 6 heads flow 87% compared to the Eddy's.

The Eddy's flow the best of the 3.
The flow #'s on are bench is low.We just us it to baseline are porting work.
Hope this helps.

Marv
 
Alright, here's what I'm going w/:

MP 5153524 heads CNC ported
Edelbrock Performer RPM intake (they don't make an air gap for a big block do they?)
750 cfm carb (I'll take any advice here)
Hyd roller cam (probably XR274HR... 224/230 duration at .050", .574/.570 lift w/ 1.6 rockers)

What's the length difference in flat vs hyd lifters? Will I have to change pushrods?

Feel free to shoot holes in my proposed setup.
 
I'm not sure what you need to make for power, but honestly if the 452s are stock ports, you can have them ported for about 1/3 the cost of any aluminum and make the power to run mid 11s. You need about 260cfm to make 475-480hp on a hydraulic cam. That's more than enough for you to exceed your goal with a well matched powertrain. That being said, the MP heads (the "452s, which are straight plug, and have a core plug and an "M" on the ends instead of Edelbrock) are as good as any aftermarket head. They ALL need work and just bolting them on can sometimes be a problem, sometimes they run well enough to meet the owner's requirements. But you will always make better power having a reputable shop check and correct the valve job. Indy, Edelbrock, MP, Source... they all have problems as delivered. Any will make the power you want without porting. The 6bbl does leave a small amount of power on the table, but compared to an RPM they are very similar. If you like a sixpac, you can make the power easy with it. You have to make sure it's tuned and runs properly.
 
If you are happy with the street manners of your current setup, but want more for the track, why not think about nitrous with small 50HP jets to meet your goal? A lot less work and a lot less money. Because you are only looking for a small HP increase, you wouldn't even need to upgrade your fuel system as long as you now have at least 3/8" lines. By the way, I just happen to have a complete six pack nitrous setup that I would sell.
 
All intake manifolds for all big block Chrysler engine are air gap in design which also includes factory intakes.

The factory designed the intake and Edelbrock copied the idea onto other engines.
 
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