Horsepower limit for out of the box Edelbrock RPM heads

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Es65Coronet

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Hello. I am curious what type of power people are pulling out of box stock Edelbrock RPM heads. I am planning a 408 build. Looking at forged Eagle rotating assembly, 10.5:1 compression, hydraulic roller camshaft in the 230@.050; .550 lift range.
Are the Eddy's a good match in this range, or will they be a bottle neck?
Thank you for your help.
 
turbodart68 said:
They are basically an aluminum copy of a factory X head with big valve. On a 408 it will be a serious bottle neck.
Click to expand...
Hmmm, a X head even with a 2.02 intake will flow, say 205 cfm untouched, while a box stock Edelbrock will flow around 250 cfm on the intake. So I wouldn't consider that an
aluminum copy of a X head, and they should do quite a bit better, especially paired with a mild cam (OP mentions 230@0.50).
Always depends on what you want, and everyone will have his own opinion or story about that. A mild 408 with Edelbrock heads will not rev to the moon but be very torquey, and maybe that is what the OP is after.
Just for illustration I attached a graph with two curves... one taken from HRM that shows a Edelbrock headed 408 with a bit hotter cam, and the other your average 408 with stock heads that falls off a log after 5000rpm.

jkfjfjA.png


PS. I nowhere said that the HRM engine was a good example of a 408, with well matched components. :)
 
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I run those,OOTB, on my 367 also with a 230/237/110/.549/.571 lift cam, and at 10.9Scr. Car went 93 in the eighth@3467pounds, .....on 87E10, shifting at 7000, on a power peak of about 5400. The Wallace calculator says 433hp.
 
They flow better than a factory X head.
And IMO, they well work really nice with your set up. It will be a low rpm engine.

The heads will be a bottle neck as well as your intake but perform well. The problem is the heads are only 175cc? And this is a well prepped iron head, like a ported X head. In general, the Edelbrock head is very good for street and light strip for up to about 370 cubic inches. As cast.

This does not mean they suck after that but they start showing there short comings. Porting the head for strip use does help a lot. Depending on what your looking to achieve, the head can take you pretty far. Fully ported the end up at 300 cfm more or less by a few cfm. In laymen’s terms, that should be enough for 600hp and some more.

As a few pro builders have said, it’s hard to get enough head on top of a stroker and if your seriously racing the car, your looking into a set of Victor heads or W9 heads.

But back to your set up....
With .550 lift, I’d run a 1.6 rocker to increase the lift and take advantage of all the heads flow that is available. Going from a stock head to a well ported head would add about 70hp to it.

As cast, the flow numbers given by Edelbrock suggest this head will make over 500 hp. But no one really looks to make max up from a as cast aluminum head. It just doesn’t make sense because there are better heads that give better all around performance. Though I think it would be cool if someone did and come on here and say I made *** amount of power from a OOTB Edelbrock head, I just don’t see the point of it unless you just wanna do it for yourself. Believe me, I do like to experiment and tinker around like that but, as I said, they are better heads to make a lot of power.
 
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I believe that
cuz shifting at 7000, my engine was ~1600rpm past the power peak or more, so working on the falling side of the curve. When I shift it like that the power rises back up to peak power after the shift, cuz my splits are 78%. I wasn't there for low ET. Just there for one timeslip; the way I like to drive it; screaming.
 
I have a big hydraulic roller cam, mildly ported Edelbrocks with 1.5 rockers, and a gasket matched RPM Airgap on my 408. It made 497 hp and 519 ft/lbs of torque. If I was trying for higher levels (which I might be soon) I would go with a full port job and 1.6 rockers. Just giving an example of what mildly ported Edelbrocks can do.
 
Didn't they run a blueprint 408 on engine masters with stock eddelbrock heads and it wasn't that good? Then they ported the crap out of them and made a ton of power.
 
thesiren74 said:
Didn't they run a blueprint 408 on engine masters with stock eddelbrock heads and it wasn't that good? Then they ported the crap out of them and made a ton of power.
Click to expand...
Yes Siren. The better curves above are from that engine featured on HRM and Engine Masters. Sure a capable builder can top that and do better with just a 367 or so with some ported heads and about the same cam. :)
But the OP clearly stated that he wants to know what can be had with box stock heads.
 
thesiren74 said:
Didn't they run a blueprint 408 on engine masters with stock eddelbrock heads and it wasn't that good? Then they ported the crap out of them and made a ton of power.
Click to expand...
The Engine Masters video series on/from Motor Trend on Demand did indeed have a 408 Stroker that is IMO handicapped by a “To small” of a head. Mentioning the video they did later on with the ported head is a great way to show how much the engine was crippled by the OOTB Edelbrock head.

Another way to look at it is it also show the head is saturated & IMO, at maximum. Perhaps a big bore short stroke engine would be different even at the same size engine
 
One user on here with a 10.5:1 408, TTI headers, and a comp PP284H, Air-Gap with a Quick Fuel 750 and stock out of the box Eddy's dyno'd at 507 at 6000 rpm and made 500 lb/ft from 3000 rpm on up. My opinion? 1.25 Hp/cubic inch isn't anything to complain about!
 
rumblefish360 said:
The Engine Masters video series on/from Motor Trend on Demand did indeed have a 408 Stroker that is IMO handicapped by a “To small” of a head. Mentioning the video they did later on with the ported head is a great way to show how much the engine was crippled by the OOTB Edelbrock head.

Another way to look at it is it also show the head is saturated & IMO, at maximum. Perhaps a big bore short stroke engine would be different even at the same size engine
Click to expand...
hmm, I'm gonna have to go find this video.
 
I remember back in the day there was an article on Hot Rod Magazine ( around 1991, no Network then :)) about an Arrow stroker engine that after some tweaks made 400 horses out of 400 cubes with, uum, swirl port heads (=318 heads). Was a big deal then. How times have changed.
 
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That’s weird because I had me Eddy’s flowed and they flowed 215 out of the box. My X heads flowed 208 on the same bench. And 450hp from a 10 to 1 410 is low. My 360 with stock X heads and 11 to 1 made 397 hp at the wheels and ran 91 in the 1/8th at 3450 pounds.
 
I don’t feel trying to think about it in terms of an actual “limit” is practical.

Think about what you’re trying to build, and then determine if that type of head fits with the rest of the combo.
Flow benches and engine dynos can vary greatly........however, I would say if you’re looking to make upwards of 500hp, and the rest of the build is on target with that type of power output, the unported RPM’s could get you there.
The one caveat being the flat tappet springs.
At the installed height they come set up at as delivered from Edelbrock, they’re not going to provide enough load to allow many of the popular faster rate cams to operate effectively at an rpm high enough to get comfortably into the 500hp range.

Basically.......valve float before the power curve reaches its peak.
Or, looking at it another way, a premature artificial peak because of compromised valvetrain control.
 
I cannot speak to the Edelbrock springs; good or bad, in my streeter.
_______________________
My first cam was the mighty 292/108 Mopar cam. I ran that with Mopar roller-tipped only,adjustable, 1.6 aluminum arms; and some Mopar HD lifters, preloaded to 1/4 turn, which turned out to be not quite enough. Shortly after break-in, I readjusted them to 1/2 turn, which has been maintained ever since. This cam was only in there for a few months, cuz I knew right away it was wrong for my combo. I sold it to a racer, lifters and all.It sure looked good on paper tho, and was a ripper after 5000.

Next came a Hughes HE2430AL, and Hughes also supplied the HDlifters,and new springs.This was my favorite. This one went 106mph in the Quarter at 3650 pounds, with 3.55s, trapping in third gear.This 2430 was a great street cam, and with overdrive made phenomenal fuel-mileage, which is partly why it was such a great street cam.This combo ran close to 200psi cylinder pressure.

Next came a Hughes HE3037AL, and Hughes again supplied the HDlifters,and new bigger springs. This one traded quite a bit of bottom end away, for a lil more up top,a good trade I thought. This is the cam that went 93.But eventually, I really missed the 2430-bottom end and so,installed a Commando box with it's 3.09low gear, a 16% boost. This last cam has been in there since spring of 2004, and has maybe 80,000 miles on it. The rest of the engine has about 100,000 on it or probably a lil more.

All these FTH combos went to 7200 with no complaints.
None of these saw a dyno.
With these, I have never heard or felt valve float, and there was never any evidence of it during freshening, which I did every winter, 6 years in a row, 2005 being the last time. All were run with 3.55s. Some other ratios were played with, but always back to 3.55s.
IMO,for a streeter, the entire combo is perhaps more important than the absolute power number. That lil 2430combo, if you math it out, was less than 350hp, and remains my favorite. It was a great ripper with 3.55s. And it was happy with 87E10; as were all of them.

More info than you probably wanted,and a lil off-topic, but possibly of some value to other readers.
 
I can't tell you how many sets of Edelbrock heads I've had on my flowbench and here are the numbers. Now subtrack what you lose with your intake, lash, pushrod angle, and pushrod deflection.

-----Edelbrock
--------Intake
.200-----128
.300-----182
.400-----215
.450-----226
.500-----233
.550-----236
.600-----242
.650-----243
.700-----243
.750
 
pittsburghracer said:
I can't tell you how many sets of Edelbrock heads I've had on my flowbench and here are the numbers. Now subtrack what you lose with your intake, lash, pushrod angle, and pushrod deflection.

-----Edelbrock
--------Intake
.200-----128
.300-----182
.400-----215
.450-----226
.500-----233
.550-----236
.600-----242
.650-----243
.700-----243
.750
Click to expand...
Do you have the info on how that compares to an X head on your flow bench or an X with a little extra work in the bowls and a gasket match? I have read an Edelbrock head is close to an X head with some bowl work and a light gasket match.
 
Garrett Ellison said:
Do you have the info on how that compares to an X head on your flow bench or an X with a little extra work in the bowls and a gasket match? I have read an Edelbrock head is close to an X head with some bowl work and a light gasket match.
Click to expand...


Sorry but no I do not. I had 8 different small block heads sitting here as I always thought I would see how fast I could get a stock type head but I sold them all last year for 40.00
I’m glad I finally wised up. Lol
 
pittsburghracer said:
I can't tell you how many sets of Edelbrock heads I've had on my flowbench and here are the numbers. Now subtrack what you lose with your intake, lash, pushrod angle, and pushrod deflection.

-----Edelbrock
--------Intake
.200-----128
.300-----182
.400-----215
.450-----226
.500-----233
.550-----236
.600-----242
.650-----243
.700-----243
.750
Click to expand...
Thanks for the info. I’ve never been impressed with the RPM. Flow benches vary and some are happier than others. For the money there are better heads out there. But it’s your money spend how you’d like.
 
rumblefish360 said:
They flow better than a factory X head.
And IMO, they well work really nice with your set up. It will be a low rpm engine.

The heads will be a bottle neck as well as your intake but perform well. The problem is the heads are only 175cc? And this is a well prepped iron head, like a ported X head. In general, the Edelbrock head is very good for street and light strip for up to about 370 cubic inches. As cast.

This does not mean they suck after that but they start showing there short comings. Porting the head for strip use does help a lot. Depending on what your looking to achieve, the head can take you pretty far. Fully ported the end up at 300 cfm more or less by a few cfm. In laymen’s terms, that should be enough for 600hp and some more.

As a few pro builders have said, it’s hard to get enough head on top of a stroker and if your seriously racing the car, your looking into a set of Victor heads or W9 heads.

But back to your set up....
With .550 lift, I’d run a 1.6 rocker to increase the lift and take advantage of all the heads flow that is available. Going from a stock head to a well ported head would add about 70hp to it.

As cast, the flow numbers given by Edelbrock suggest this head will make over 500 hp. But no one really looks to make max up from a as cast aluminum head. It just doesn’t make sense because there are better heads that give better all around performance. Though I think it would be cool if someone did and come on here and say I made *** amount of power from a OOTB Edelbrock head, I just don’t see the point of it unless you just wanna do it for yourself. Believe me, I do like to experiment and tinker around like that but, as I said, they are better heads to make a lot of power.
Click to expand...

I am going to see how much i can get out of a set OOTB Edelbrock's i can get with a 340, will not be on the dyno, but i will have a time slip from 1/4 mile. And my 318 goes 91 in the 1/8th with OOTB Edelbrock's now.
 
I've read an article over on Moparts that the MP commando aluminum head has some impressive flow potential but the cost is about on par with a set of Brodix B1-BA heads. I wish Edelbrock would start making a copy of a bare 59 degree B5 that used the .650 offset rockers.
 
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