Moparts
Eldebrock RPM's vs. 440 Source Stealth heads**UPDATE**
Posted By: '72CudaRacer
Eldebrock RPM's vs. 440 Source Stealth heads**UPDATE** - 06/19/13 01:49 AM
Trying to decide which way to go and would welcome some input from from other racers in my position.
First, some back ground. I built this engine (440 +.030, MP .590 cam, Ross domed pistons 99501, H beam rods, Hooker super comp headers, 1050 dominator carb) with 440 Source Stealth heads. One of them cracked where the early castings were prone to crack (end exhaust port into the spark plug hole, not really cost effective to repair). Then I put my trusty cast iron 452's (some port work) on and was OK with that. Doing so I added 40 lbs back to the front of the car and lost .3 ET (from 6.50s to 6.80s) Now one of the 452's is cracked and I have to make a dession as to which way to go.
I'm not looking for 700 hp or even 650 hp because the car is not tubbed and runs 11.5 X 29.5 slicks on SS leaf springs. I am also trying to keep the cost down as much as possible.
I'm looking at Indy SR heads, but they may be over kill for my needs, plus a lot of others issues to deal with (such as external oil lines, differnt push rods, valley plate, angled plugs, raised exh ports, ect)
All that brings me back to basicly two choices, 440 Source Stealth heads or Eldebrock RPM's. On paper they look very similar. As cast they flow as good as a preped 906 or 452.
All that to ask this; OOB, which head do you feel would be the better choice for me?
Thanks for your help,
Brian
Posted By: Chris2581
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 02:01 AM
Even though I have Stealth's and so far am happy with them,I would go Edelbrock.The only 2 reasons I went with Stealths was the cost and that they look like the stock Mopar heads.For a dedicated race car Edelbrock would be my choice.
Posted By: 69dart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 02:46 AM
I put a set of stealth heads on the 383 in my roadster. They required about 4 hours of grinding to get the pushrods to clear but otherwise I haven't had any complaints. I would buy them bare and let your machine shop set them up as you probably won't be using the springs, locks or retainers that they come with.
My little 383 has gone 9.83 @ 133 with them.
Posted By: sam64
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 03:01 AM
angle plugs looks to be the factor.
Posted By: 69CHARGERMD
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 03:16 AM
I run the edelbrock RPM performers.
Have run a best of 10.04 at Norwalk last year.
No complaints.
Dwayne Porter did the heads.
Doug.
Posted By: mopar65
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 03:24 AM
Quote:
I run the edelbrock RPM performers.
Have run a best of 10.04 at Norwalk last year.
No complaints.
Dwayne Porter did the heads.
Doug.
Hey doug how have you been. would like to add those same heads out of the box ran 10.50 at 125-126. also ? for the op what about a set of the indy EZ heads? i pretty much have a out of box set of them on my 93 pump gas 440 3520 pound 1973 big block dart.have been a best of 10.49 at 125. Dwayne also did the heads for me. Bobby
Posted By: Big Squeeze
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 03:47 AM
I don't understand the question here???...
Stealths are a cheap, Chinese copy of the Edelbrocks with the outside casting changed and plug angle moved...Modern even uses the EXACT same CNC porting program to port both heads...So, the question should be do you want a high quality, American made cylinder head or do you want to support the Chinese knock off??
Personally, I have not and will not build a motor with Stealth heads....
Posted By: calrobb2000
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 04:27 AM
hi,
the eldebrocks will be higher quality and not need anything to run with your combo . i have used the 84cc with a 590 cam ,no machiene work needed !
no expencive trp to machiene shop for extra bs !
Posted By: Triple Threat
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 04:55 AM
Quote:
I don't understand the question here???...
Stealths are a cheap, Chinese copy of the Edelbrocks with the outside casting changed and plug angle moved...Modern even uses the EXACT same CNC porting program to port both heads...So, the question should be do you want a high quality, American made cylinder head or do you want to support the Chinese knock off??
Seems like a pretty simple answer, you already had the stealths crack, why go down that path again?
Posted By: Thumperdart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 05:52 AM
I`d go E-Brocks but nothing is out of the box in my opinion and mine and many others I know of needed a bit of work.......nothing major though. If you can swing a mild clean up and bowl work and you`re off and runnin.
Posted By: viperblue72
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:28 AM
I agree that Edelbrock would be a better choice. They also flow better ootb than a stealth. I think the edelbrock ootb will flow about 285 where as the stealth flow 265 iirc. Have you considered the indy ez?
Posted By: tex013
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 11:34 AM
Why not the CNC Stealths ?. Certainly a cost effective choice. I know there have been stealth faults but there has also been eddy faults as well as issues with Indy stuff . I guess it also matters if you get bent up over chinese or usa stuff . I have seen crap from both .
I ran stealths from 2008 no worries , i have just fitted some Modern Stealth cnc heads and am more than happy with the result , i used my own springs retainers . So many people use and recommend Jeff do you think he would dump his reputation if he thought them no good .
My program benefittedvfrom them , for allout race probly not the best . Straight plugs , a big plus . Eddys will probly need longer pushrods extra cost . Flow the same numbers . I don'think you will see much if any performance difference between the two .
My two cents
Tex
Posted By: gregsdart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 11:46 AM
Can you get a single replacement stealth, provided you still have the other one? If not, then it all boils down to what floats your boat. Unless you change a number of things in the combo, low speed torque (launch, traction) won't change much. A bigger port will add more to the upper rpm range, but not too much to the lower rpm range.
Posted By: Chris'sBarracuda
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 12:16 PM
Quote:
Can you get a single replacement stealth, provided you still have the other one? If not, then it all boils down to what floats your boat. Unless you change a number of things in the combo, low speed torque (launch, traction) won't change much. A bigger port will add more to the upper rpm range, but not too much to the lower rpm range.
.. Or just a pair of bare Stealth heads and put your stuff in them..
Another thought, aren't Indy EZ's were a direct bolt on.. 
Do they come in a M/W port.?? That might be a thought as well..
Chris.. 
Posted By: viperblue72
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 01:50 PM
Quote:
Quote:
Can you get a single replacement stealth, provided you still have the other one? If not, then it all boils down to what floats your boat. Unless you change a number of things in the combo, low speed torque (launch, traction) won't change much. A bigger port will add more to the upper rpm range, but not too much to the lower rpm range.
.. Or just a pair of bare Stealth heads and put your stuff in them..
Another thought, aren't Indy EZ's were a direct bolt on.. Do they come in a M/W port.?? That might be a thought as well..
Chris..
I asked that too then realized he has dome pistons, may not work.
Posted By: JohnRR
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 02:32 PM
If you need straight plugs and cost is not a huge factor the MP 452 head is the Ebrock RPM with a straight plug.
No matter which head you buy don't run them out of the box , have the valve job at least fixed .
Posted By: 383man
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 03:16 PM
I was going to use the RPM heads but then went and bought the EZ heads from Dwayne Porter. I felt the EZ heads have more overall potential as I may want to step mine up more in the future and I only spent about $300 more to get the EZ heads from Dwayne. Ron
Posted By: Anonymous
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 05:07 PM
Quote:
I don't understand the question here???...
Not to tough to figure out.....
Edelbrock heads=$1750, plus need to be checked for guide clearance and valve job
Stealth heads=$1000, plus need to be checked for guide clearance, valve job, and pushrod clearance
CNC Stealth=$2000, Ready to go, checked by Modern Cyl. Head
CNC Stealth is a no-brainer
Posted By: deaks
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 05:08 PM
HI Brian
I run MCH RPM's milled to 76 cc, with .590 cam and JE domes in my 440 and a 950 hp holley.
Mick
Posted By: Copper Dart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 05:21 PM
Where are the Eddy heads made? Are they not overseas too?
WOW am I Confused!
ricky
Posted By: dogdays
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 05:43 PM
Edelbrock has their own foundry right here in the USA. Look at their literature, they say it again and again.
R.
Posted By: BradH
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 05:58 PM
Where did the Stealth head crack and is it not repairable?
I don't bother following the Stealth-related posts often; is this a common problem with them?
I don't recall the Edelbrocks having cracking issues, etc., although I've seen first-hand how IMO they still need to have the guide clearances & valve jobs checked & corrected OOB.
Performance-wise there shouldn't be any significant difference with the same level of prep work, considering Brandon's R&D for port & chamber design was simply sending an Edelbrock Performer RPM to China along w/ an OEM iron head and giving the foundry the following instructions:
1. Make new head rook rike Ederbrock on inside
2. Make new head rook rike Chrysrer iron head on outside
(My apology to all Asian and Asian-American readers who take offense to my accent parody.
)
EDIT: Just re-read the orginal post and saw where the OP stated
"One of them cracked where the early castings were prone to crack (end exhaust port into the spark plug hole, not really cost effective to repair)." 
Posted By: drmopar
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:01 PM
I bought a set of CNC'd stealth heads for my 451 I had in my last road runner vert and they still needed to be clearanced for pushrods. Just sayin.
If it were a racecar, Edelbrock heads. If it was a show car (FAST looks) then Stealth all the way.
Posted By: JohnRR
Re: Eldebrock RPM's vs. 440 Source Stealth heads *DELETED* - 06/19/13 06:30 PM
Post deleted by JohnRR
Posted By: Thumperdart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:31 PM
Quote:
Quote:
I don't understand the question here???...
Not to tough to figure out.....
Edelbrock heads=$1750, plus need to be checked for guide clearance and valve job
Stealth heads=$1000, plus need to be checked for guide clearance, valve job, and pushrod clearance
CNC Stealth=$2000, Ready to go, checked by Modern Cyl. Head
CNC Stealth is a no-brainer [/quote
You still end up with $2,000 worth of japanese crap.......... 
Posted By: Triple Threat
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:35 PM
Quote:
Quote:
Quote:
I don't understand the question here???...
Not to tough to figure out.....
Edelbrock heads=$1750, plus need to be checked for guide clearance and valve job
Stealth heads=$1000, plus need to be checked for guide clearance, valve job, and pushrod clearance
CNC Stealth=$2000, Ready to go, checked by Modern Cyl. Head
CNC Stealth is a no-brainer [/quote
You still end up with $2,000 worth of japanese crap..........
Unlikely they're made in Japan. Not all countries are the same, and there are chinese foundries that produce extremely high quality products, they're just not cheap so people don't use them.
If it was my Money RPM heads or the EZ head.
Posted By: JohnRR
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:36 PM
Quote:
You still end up with $2,000 worth of japanese crap..........
They wouldn't be crap if they were made in Japan 
...
Posted By: VincentVega
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:51 PM
Guess I'll go with bare Edelbrock heads... just noticed the aluminum "452" heads (good flow out of the box) but I think I'd rather screw around with angle plugs anyway
casting problems are scary, and hard to see
Posted By: Thumperdart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 06:56 PM
Quote:
Quote:
You still end up with $2,000 worth of japanese crap..........
They wouldn't be crap if they were made in Japan ...
How`s that, did you see the above post? Ever see another head made here do that? Japanese, Chinese not sure of the differences I guess.
Posted By: Skeptic
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 07:34 PM
Quote:
\ Hope I don't get banned for this ....
Really John, that's just trolling there. That engine was hydraulic locked or the head bolts weren't torqued properly.
Thumper- they are Chinese heads....
I bought the Eddie heads- the Stealths weren't on the market yet- and would recommend them, just because they are made in the USA. The Eddie heads are known to need setup work, no different than ANY aftermarket head- some of the MP stuff needs Major work. I'm having Brian @ IMM do a full setup and porting appropriate to my build. He's given me a very reasonable price and I like supporting a local shop.
Posted By: an8sec70cuda
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 07:43 PM
Quote:
Quote:
Where did the Stealth head crack and is it not repairable?
Hope I don't get banned for this ....
Holy crap! What's the story on that head?
Posted By: 540challenger
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 08:04 PM
Quote:
Guess I'll go with bare Edelbrock heads... just noticed the aluminum "452" heads (good flow out of the box) but I think I'd rather screw around with angle plugs anyway
casting problems are scary, and hard to see
IF i remember right the MP 452 head is cast by edelbrock and it is basiclly a RPM head with straight plugs
Posted By: pittsburghracer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 08:08 PM
Casting problems occurred in the second run on these heads. In-proper heat treating but has long been taken care of. A Friend of mine was the owner of said set but they sat on a shelf for a couple of years before he used them. He then did some at home porting and installed them on his car. Not sure of the time period but one did develop some cracks. I told him to talk to Brandon and after a few conversations they were both replaced with a NEW set of heads long after the purchase. Check recent history with these heads and other than the same issues found on MOST after-market heads (tight valve guide, not the best valve job) their track record is pretty good.
Posted By: oldtimer5151
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 08:17 PM
The rpms have angled plugs and the hooker 2 inch work on mine. The rpms like any other head will need a multi-angle valve job and springs for your cam. I have the rpms and to me they had very little foundry shift in the castings. I know nothing about the other heads only what I have read. You will need to have the intake port ported to really see any rear benefit, because the exhaust has good flow and may need very little work. With the .590 cam I think you would benefit more from the rpms than the big victors.
Posted By: hudsonhornet7x
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 09:30 PM
on a side note about rpm heads, does anyone know how fast these heads could push a b-body?
Also, if the heads were fully ported what is the ideal cubic inch for these heads? In other words what works well, and what is too big?
Posted By: CompWedgeEngines
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 09:46 PM
Been 10.07 @132 in a 68 GTX weighing 3600# race weight. Easy nines in a lighter car for sure. Cam could have been optimized as well, but this guy is a hardcore bracket racer, and didnt also want to deal with safety equipment running in the nines. He was running a 493 combo. They will work great from 440-512 C.I. All standard off the shelf stuff, not even ported intake etc...very user friendly.
Posted By: oldtimer5151
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 09:47 PM
The rpms were engineered to flow their best at .600 and maybe a little more. The victors are for bigger inch, big roller, intake, and exhaust system.
Posted By: pittsburghracer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 09:50 PM
Quote:
on a side note about rpm heads, does anyone know how fast these heads could push a b-body?
Also, if the heads were fully ported what is the ideal cubic inch for these heads? In other words what works well, and what is too big?
Not a B body but a Friends duster has gone 8.80's-8.90's with Edelbrock heads, solid lifter cam, and a tunnle-ram. App 500 ci.
Posted By: JohnRR
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 09:52 PM
Quote:
Quote:
Quote:
Where did the Stealth head crack and is it not repairable?
Hope I don't get banned for this ....
Holy crap! What's the story on that head?
I don't remember but when I saw it I right clicked SAVE ... the person that posted it up had more than one that was broken like that. I doubt they were hydro locked, this was a known issue with the early stealths, I hope for the sword swallowers sake that they don't have that issue anymore.
Dom, there is a huge difference between stuff made in Japan and the stuff made in China , Japanese stuff was on par with current china back in the 70's , much better today .
Posted By: Thumperdart
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 10:38 PM
Quote:
Quote:
Quote:
Quote:
Where did the Stealth head crack and is it not repairable?
Hope I don't get banned for this ....
Holy crap! What's the story on that head?
I don't remember but when I saw it I right clicked SAVE ... the person that posted it up had more than one that was broken like that. I doubt they were hydro locked, this was a known issue with the early stealths, I hope for the sword swallowers sake that they don't have that issue anymore.
Dom, there is a huge difference between stuff made in Japan and the stuff made in China , Japanese stuff was on par with current china back in the 70's , much better today .
Ya, my ADD was on kill when I posted that and I forgot that Japan in many ways has it together however China and Taiwan................ 
Posted By: hudsonhornet7x
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/19/13 11:07 PM
Competition wedge you have a pm
Posted By: Big Squeeze
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 12:56 AM
Quote:
Quote:
I don't understand the question here???...
Not to tough to figure out.....
Edelbrock heads=$1750, plus need to be checked for guide clearance and valve job
Stealth heads=$1000, plus need to be checked for guide clearance, valve job, and pushrod clearance
CNC Stealth=$2000, Ready to go, checked by Modern Cyl. Head
CNC Stealth is a no-brainer
What I meant by "I don't understand the question" is that they are the same head (performance wise) when prepped the same...so it boils down to if you want to support an American made product or a Chinese knock-off....sure, it's "a no brainer" if you don't care about jobs in this country...
Posted By: Dodgem
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 01:10 AM
Quote:
I agree that Edelbrock would be a better choice. They also flow better ootb than a stealth. I think the edelbrock ootb will flow about 285 where as the stealth flow 265 iirc. Have you considered the indy ez?
Go edelbrock they will produce 40 more HP OOTB better than Stealth. I have hand ported both and the edelbrocks are much nicer fit and finish on and off the motor. Lets say the stealths are well chinessee. seats hang down into combustion chamber or are not flushed with it better than a 45 year old iron head but bot near as nice as an edelbrock!
The confusion comes when CNC ported Stealths are close to the Edelbrocks (within 10 CFM) but OOTB many get the 265/267 number for the Steaths and 285/287 for the OOTB Edelbrocks. My local guy got 257 for the stealth and 285 for eddies on his flow bench. A little hand porting on either can go a long way.
Posted By: CompWedgeEngines
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 01:15 AM
I agree with this information and have found very similar results...Good straight info...
Posted By: Dodgem
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 01:29 AM
a buddy of mine ran the edelbrocks OOTB on a 448 inch 440 with a .590 mp cam and they worked great.
On the stealths i hand ported did the bowels (I'd say a big gain there) port match smoothed and worked the pushrod pinch about .100 but not overboard after I was done they flowed 285 on the same bench the guy that owns the machine shop got 257 with an out of the box stealth he said a nice gain with the work I did.
Knowing the clearance issue with 3/8 pushrods on the stealth I clearanced quite a bit and when buddy assembled the motor had to do one or two spots some more. It's almost like the head casting is inconsistant.
Still better than iron heads and way way nicer to port! Porting iron sucks!!!
Posted By: VernMotor
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 01:51 AM
I have the mopar/eddy heads been 4 years now. Very happy with them,
Posted By: Ari440
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 03:11 AM
Quote:
Quote:
on a side note about rpm heads, does anyone know how fast these heads could push a b-body?
Also, if the heads were fully ported what is the ideal cubic inch for these heads? In other words what works well, and what is too big?
Not a B body but a Friends duster has gone 8.80's-8.90's with Edelbrock heads, solid lifter cam, and a tunnle-ram. App 500 ci.
what dos this car weigth
what carbs on the tunnelram
what solid cam
very nice combo
Posted By: pittsburghracer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 03:40 AM
Quote:
Quote:
Quote:
on a side note about rpm heads, does anyone know how fast these heads could push a b-body?
Also, if the heads were fully ported what is the ideal cubic inch for these heads? In other words what works well, and what is too big?
Not a B body but a Friends duster has gone 8.80's-8.90's with Edelbrock heads, solid lifter cam, and a tunnle-ram. App 500 ci.
what dos this car weigth
what carbs on the tunnelram
what solid cam
very nice combo
I won't post a weight or cam specs because I'm not sure. Its a Indy tunnel ram with (2) 750's. Now for the good part. He ported the heads himself (first attempt) under the guidance of Tom Hemphile. Not bad for a 23-24 year old. His Fathers 69 charger has gone 8.60's with B1-BS heads and an old weiand tunnel ram.
Posted By: CompWedgeEngines
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 03:50 AM
Yea, but the Duster has a B1 sticker on the scoop...!!!!!
Posted By: pittsburghracer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 04:09 AM
Quote:
Yea, but the Duster has a B1 sticker on the scoop...!!!!!
Hey Todd SHHHHHHH. That's worth 50hp. For each carburetor.
Posted By: Twostick
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 06:16 AM
Quote:
Quote:
Quote:
I don't understand the question here???...
Not to tough to figure out.....
Edelbrock heads=$1750, plus need to be checked for guide clearance and valve job
Stealth heads=$1000, plus need to be checked for guide clearance, valve job, and pushrod clearance
CNC Stealth=$2000, Ready to go, checked by Modern Cyl. Head
CNC Stealth is a no-brainer
What I meant by "I don't understand the question" is that they are the same head (performance wise) when prepped the same...so it boils down to if you want to support an American made product or a Chinese knock-off....sure, it's "a no brainer" if you're the stereotypical Joe Dirt Mopar guy that's spending money on a motor he really can't afford when he should be buying clothes for his kids AND doesn't care about jobs in this country...
And the E-brock is pretty much a Mopar knock-off right down to the stone age combustion chamber albeit with better flowing ports.
What I don't understand is why Edelbrock made them with those chambers when they already have patterns for fast burn chambers proven to make a bunch more power with 10 deg less timing on other flavors of engines. Never mind less chance of detonation and cap walk.
Kevin
Posted By: BradH
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 02:07 PM
Quote:
And the E-brock is pretty much a Mopar knock-off right down to the stone age combustion chamber albeit with better flowing ports.
Yes... and no. Chamber design definitely "old school", other than adding an angled plug. However, looking at cross-sections of an OEM head and an E head show some pretty clear differences in port design. They're straighter and actually have reasonable short turns that the OEM stuff overlooked.
Quote:
What I don't understand is why Edelbrock made them with those chambers when they already have patterns for fast burn chambers proven to make a bunch more power with 10 deg less timing on other flavors of engines.
The same thought crossed my mind, too. And when Edelbrock started previewing a Performer RPM Xtreme that looked to incorporate a Victor-style chamber w/ the current Performer RPM architecture, I thought that was a move in the right direction.
Then, probably because of the economy taking a big hit, the Performer RPM Xtreme mysteriously disappeared from all Edelbrock web sites and literature, as if it never existed in the first place...
Posted By: VincentVega
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 02:10 PM
what, really? I thought they used a modern combustion chamber design??
This is big shocker to me, as I was counting on that to help me pass emissions in my state (yes, my 78 is subject to the sniffer test, HC and CO, but not NOx)
now I don't know what I am going to do... are there any other heads out there?
Edit: just took a look at the Victor heads, great looking chamber design.. but I wonder if they are too much intake port for a street engine?
Posted By: dogdays
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 05:10 PM
There's no queation that the Edelbrock head combustion chamber is a copy of the 915 chamber, that's a 1967. Are the ports close? I don't know, but Steve Dulcich found that the 915 head had good swirl. That, added to the ability to build squish makes the 915 pretty desirable.
IMHO the 1968 chamber was a step in the wrong direction. I believe one of the problems was the MOPAR engineer's acceptance of low precision in the manufacturing process. Even though they had the area in place, the top of the piston was too far away from the head squish area. So, there was a large amount of cool, unburned hydrocarbons that never got taken care of. Remember that the squish area needs to be 0.040" or less, but the OEM design left at least 0.080" on most of the big blocks. The open chamber killed their "problem" which was caused by leaving the piston top too far down at TDC.
If you make sure to get the piston and the head squish area to be within 0.040" of each other, though, I think emissions will be better and depend more on camshaft and carb setup.
it is too bad that Edelbrock didn't put a better chamber in those heads, as was said before they had several examples of better chambers in production! Perhaps they were concerned about high compression dome fitment. Using the 915 chamber made sure that high compression domed pistons would fit.
R.
Posted By: VincentVega
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 05:37 PM
Good read, thanks for posting that. I spoke to my dad for another perspective and he said he thought the victor would be too much head for my big heavy street cruiser (late B 4 door) and that the RPM would still work well with the closed design. He may be intrinsically biased though towards that style head since he still has his 67 440
Not many options to pick from, guess I will stick with the RPMs in my build plan and factor in good quench. thanks
Posted By: 72Swinger
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 06:15 PM
Wonder if the new E-Street 75cc chamber heads add efficiency to the chamber? Think I also read the new Indy EZ has a "new style" chamber. My build is gonna be a 91 octane deal and a good chamber would be a deciding factor. I dont get to excited when I see a head with an old style open chamber either.
Posted By: VincentVega
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/20/13 06:21 PM
I looked at those too, but it said something about not compatible with roller cams, so that was a definitely red light for me
Posted By: viperblue72
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/21/13 01:03 AM
Quote:
There's no queation that the Edelbrock head combustion chamber is a copy of the 915 chamber, that's a 1967. Are the ports close? I don't know, but Steve Dulcich found that the 915 head had good swirl. That, added to the ability to build squish makes the 915 pretty desirable.
IMHO the 1968 chamber was a step in the wrong direction. I believe one of the problems was the MOPAR engineer's acceptance of low precision in the manufacturing process. Even though they had the area in place, the top of the piston was too far away from the head squish area. So, there was a large amount of cool, unburned hydrocarbons that never got taken care of. Remember that the squish area needs to be 0.040" or less, but the OEM design left at least 0.080" on most of the big blocks. The open chamber killed their "problem" which was caused by leaving the piston top too far down at TDC.
If you make sure to get the piston and the head squish area to be within 0.040" of each other, though, I think emissions will be better and depend more on camshaft and carb setup.
it is too bad that Edelbrock didn't put a better chamber in those heads, as was said before they had several examples of better chambers in production! Perhaps they were concerned about high compression dome fitment. Using the 915 chamber made sure that high compression domed pistons would fit.
R.
I bet you will find .080 was on the highest of compression 440. By 1973 it was more like .170 . Yes, one hundred seventy lol. And if you do the math, the true compression of a smog 440 is 7.7-7.8 to 1.
Posted By: Anonymous
Re: Eldebrock RPM's vs. 440 Source Stealth heads *DELETED* - 06/21/13 01:54 AM
Post deleted by tboomer
Posted By: d-150
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/21/13 02:42 AM
i used 440 source heads in my dakota,edelbrocks would not fit under power brake booster.had machine shop check them out guides etc checked out good.wether made in china or japan there is a place for these heads mentioned earlier stock height,stock look, straight plugs.
Posted By: viperblue72
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/21/13 04:03 AM
What's wrong with Joe Dirt?
.
His cars are cooler than yours.
Posted By: Sport440
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/21/13 04:37 AM
I dont understand the Question?
Id say if your only looking for a single head replacement ,by the el cheapo newer model stealth to match your other stealth head.
Now if you want a total switch over of heads, different story.
Do you have a "Joe Dirt" Budget or a "Donald Trump" Budget.
Joe Dirt
Donald Trump
Posted By: '72CudaRacer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/23/13 04:25 AM
Desision made. Edelbrocks will be here monday. After everything is added up, the Edelbrocks were less than $400 more than Stealths. Thanks for all the replys guys.
Brian Dunnigan
Posted By: '72CudaRacer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/23/13 04:37 AM
Quote:
Do you have a "Joe Dirt" Budget or a "Donald Trump" Budget.
Budget? Are you kidding me? I'm a drag racer, there is no budget. But there is my wife...
Posted By: Big Squeeze
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/23/13 04:41 AM
Quote:
Desision made. Edelbrocks will be here monday. After everything is added up, the Edelbrocks were less than $400 more than Stealths. Thanks for all the replys guys.
Brian Dunnigan
Nice....
Posted By: tboomer
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/23/13 09:21 AM
Quote:
Desision made. Edelbrocks will be here monday. After everything is added up, the Edelbrocks were less than $400 more than Stealths. Thanks for all the replys guys.
Congrats,Brian!! I am sure you will be happy with them!!
Posted By: Dodgem
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/23/13 05:19 PM
You will like the eddy's
Posted By: VernMotor
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/23/13 05:26 PM
You did the right thing !
Posted By: bobdog106
Re: Eldebrock RPM's vs. 440 Source Stealth heads - 06/26/13 06:58 AM
I have my closed chambers Eddy's that were cnc'd by Modern on my street car into the 9's. They have worked great for several years with no issues.
...maybe then he can offer some first hand, REAL experiences... 
