which would be better

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stroked 340 said:
Half of what you read in those rags is printed just to get people to buy them...
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It's all the fluffy wording in there descriptions and such. I'm with DGC on his #1 statement above. All things within reason can be beileved, now, will someone who just won lotto lend me a few million so I can run indepentd and offical FABO tests!
 
1wild&crazyguy said:
Thing you must see is that when building around a head, you able to compensate...that is as long as the flow is there.
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Humm, no, more like, don't build a street performance engine with pro stock heads. If you have a set of indy heads to build with, and decide to build around the head, do so accordingly. Don't build a mileage master with throttle body FI and emmissions in mind.
(OK, extreme example, LOL w/me, but that is where I was going with it. )

Now some might say...''oh, but the magnum has'em stock''-1.6
Oh yeah??? well I don't know about you, but I run a decent sized cam when I'm building power and those non roller pedestal rockers don't have rollers last time I checked, so I guess those just useless to me unless I want to trash my guides and simply wear sht out.
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You can get roller rockers for the Magnum head. An extra expense that is worth it? Only the pocket/wallet will say. I like to get the cam lift I want rather than use a higher ratio rocker to get there. But that isn't allways the case...as in my current case (cam in use) though I'd rather have the cam than a higher ratio rocker myself.

But in this guys case, a choice between heads and there rocker ratio differences... a higher ratio could be a benifit. So far, his build perameters are a unknown and your assuming and pushing the idea of a higher performance build than anyone else on here assumes. Your going right to the max and extremes of things. Point in case is;

Guide wear. Any head will have it and more so and quicker in a higher HP build. High performance = high mantaince. Is this guy there or not?

And port volume?....better cc those magnum's cause 155cc on j head aint big when it comes to 340-360cid...btw notice the higher roof by looking at the port window on a j head? think that has a lil to do with why they might flow more?, yeah.
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A higher port roff is allways perfurable. How is the port relation between heads vs where they sit in relatuion to the exit at the valve vs angle and bend?
Just because head Z has a higher port doesn't automaticaly mean it will out flow head P with lower roof hights. Romove your thinking from a MoPar hea and look at other manufactures heads and there flow rates vs port location and relation and cc amounts.

I said before and I'll say it again, the magnum heads were designed with smog requirements and fuel injection in mind, closed chambers help this, but also can impede flow=shrouding.
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In the big picture, it's small potatos. Something to avoid, sure. Why is it other manufactures have a semminly not a care in the world about it and there engines still make big power? Valve shrouding and it's effect is over rated like a scared kid and a VooDoo doll.
But again, if you can avoid it in a power house build, do so. Will it make a hge difference on a 275 HP engine? Maybe so, but I think the peanut crumbs that everyone is worried about is crazy.

smaller port window-'sometimes the case' is either a mix matched combo in which air speed from a smaller port window is only a band aid for poor blue printing/too big a carb etc.. and usually ends up as a trade off else where in the power range.
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It's not poor blue printing, it's poor thinking. Blue printing has nothing to do with this.

As for low lift flow ...I didn't know high 190's @.300 & 230's and high 240's at .400 lift was crummy low lift flow, I must have missed that in my mopar engines book...lol
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You wanna run the air fuel through the head curve passed me again?
Run this pasted the OE posters build and not what your thinking of. You keep beating this horse half to death when the unknowns are still lingering.
If I follow what your saying like a blind idiot, and you know I'm not, a set of INDY heads should be used on my daily driver for mileage reasons.:-D
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rumblefish360 said:
Humm, no, more like, don't build a street performance engine with pro stock heads. If you have a set of indy heads to build with, and decide to build around the head, do so accordingly. Don't build a mileage master with throttle body FI and emmissions in mind.
(OK, extreme example, LOL w/me, but that is where I was going with it. )


You can get roller rockers for the Magnum head. An extra expense that is worth it? Only the pocket/wallet will say. I like to get the cam lift I want rather than use a higher ratio rocker to get there. But that isn't allways the case...as in my current case (cam in use) though I'd rather have the cam than a higher ratio rocker myself.

But in this guys case, a choice between heads and there rocker ratio differences... a higher ratio could be a benifit. So far, his build perameters are a unknown and your assuming and pushing the idea of a higher performance build than anyone else on here assumes. Your going right to the max and extremes of things. Point in case is;

Guide wear. Any head will have it and more so and quicker in a higher HP build. High performance = high mantaince. Is this guy there or not?


A higher port roff is allways perfurable. How is the port relation between heads vs where they sit in relatuion to the exit at the valve vs angle and bend?
Just because head Z has a higher port doesn't automaticaly mean it will out flow head P with lower roof hights. Romove your thinking from a MoPar hea and look at other manufactures heads and there flow rates vs port location and relation and cc amounts.


In the big picture, it's small potatos. Something to avoid, sure. Why is it other manufactures have a semminly not a care in the world about it and there engines still make big power? Valve shrouding and it's effect is over rated like a scared kid and a VooDoo doll.
But again, if you can avoid it in a power house build, do so. Will it make a hge difference on a 275 HP engine? Maybe so, but I think the peanut crumbs that everyone is worried about is crazy.


It's not poor blue printing, it's poor thinking. Blue printing has nothing to do with this.


You wanna run the air fuel through the head curve passed me again?
Run this pasted the OE posters build and not what your thinking of. You keep beating this horse half to death when the unknowns are still lingering.
If I follow what your saying like a blind idiot, and you know I'm not, a set of INDY heads should be used on my daily driver for mileage reasons.:-D
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Rob, we [Dave & I] were comparing old to newer magnum stuff-stock and modified, no body is lost here, or at least not us 2, you did read 'low lift flow', right? so you should know the lift range were talking, right?lol

You are now using the far end of examples with the pro stock head mention...You should know the lift range we are revolving around-hence all the low lift flow talk. You just generalized even more by relating your example of street motor 'whatever cid' with prostock heads [only fit hemi's] to a small cid/ or low rpm range, but it's because your efforts are to catch me slippin here somewhere, or is it not?
I'm not explaining every aspect here, too many variables, being a tuner I know this but I'm not trying the write a 'how it works' book

btw ...more lift is HP, nothing wrong with adding higher ratio rockers and making more power, even in a head that stalls out just below the increased max lift 'say went from .500 where peak flow is, to .530' from the higher ratio adds power because you just lengthend time for flow and opened the valve to the peak flow@ it's lift range 'by virtue of faster/higher lift' because you now put the peak flow @ lift in/closer to the longer duration opening/closing cycles of the cam used.
You can take a head that stalls at .450 and stick a .557 cam in it and make more power due to the add'd duration for flow at peak lift, could even go bigger to an extent.
If you run over .500 lift on the street and expect longevity in the guides by avoiding too much side loading, you need to run some roller tips, can do with out=yes, will it last and not eventually ruin the valve job=NO.

btw, how many times does someone ask this 'whats better' question with nothing else to go by?
Thats why you get the all or nothing response, cause thats all you can give, which I think we've covered most-low lift flow-head features/benefits, which will actually make the diff and what has the best potential...and so on.

Valve shrouding....can be worth 7 or so cfm depending on the valve size and relation to the chamber wall.
Other manufactures? try most all stock stuff, let alone compensation in flow to overcome any significant/insig flow loss.
Car companys are not building around this issue let alone the idea of obtained 100% VE and HP per cid, kinda how you can raise the hp of a sb dodge, or whatever, a 100 hp fairly easily with bolt ons & in's and piston swaps etc..know what I mean?

blue printing go's beyond thousandths and cc's.
when you house was build don't cha think they had standards for cooking range size/power requirement?, types of sinks for the time, which pipe to use galvy/copper?

btw, on the roof height deal...ha, ok...if head Z [which better be a mopar sb head cause thats what 'we' are talking about] has a higher roof and also has a good workable short turn over head D-... Z wins in the flow/potential flow arena.

something you are missing is that , it ain't about the 290's a j head can flow fully done, it's the fact that it still flows 200's at .300, 240's-250's at.400 and 270's at .500....
what about a prostock head??
or for that matter wether the op is doing mild or wild on the street?
That head will work everywhere on a mid sized 320+ inch motor


and about the horse and the beating 'n such lol, Someone said the magnum head was better than the j head in stock and modified, or at least they have not come out and said any different. thats no true and so I will smash this horse into puree if I have to.ha ha

I don't always take/read posts for all the tone the poster may have inserted, so maybe I'm taking this wrong 'what u are saying to me' that is..
But I know you know what I meant, it's frustrating though when someone won't be or isn't on the same level as to understand the realm in which I'm speaking of, thats where we get mixed up.
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dave, heres the hughes page i found about the/a comparison, sorry if i missed the one you mentioned.
http://www.hughesengines.com/TechArticles/1headflowcomparisonsupdated112009.php

as for flow benches, if you don't know how to manipulate the #'s on a flow bench then you don't know as much about a flow bench as you think.

I'm done, there is plenty of info out there and most of it is based on the popular thing of the week, or what so n so likes or runs.


the op is not even chiming in, total waste.
 
but it's because your efforts are to catch me slippin here somewhere, or is it not?
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closer to ranting. He he he he

btw, how many times does someone ask this 'whats better' question with nothing else to go by?
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More times than I have hair folicals on my head, and I have a full carpet up top.

something you are missing is that , it ain't about the 290's a j head can flow fully done, it's the fact that it still flows 200's at .300, 240's-250's at.400 and 270's at .500....
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Not missed, but that is something that is allways pointed out and then judged to be the reason that head is worthy and the other is not and then trashed. Heaven forbid someone actually uses it and gets hammered by useing it.

so I will smash this horse into puree if I have to.ha ha
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Sounds like a new sig. line to me! Wheres the Ford avatar/smiley?!?!?!

Allways good jouisting with ya.
 
wow this got out of hand lol
well my build perameters are mostly price related i wanted to know which would be the best to start with to get to my 400+ hp goal

i am just trying to get a good direction to go so i can save while i am in iraq
 
Are you serious!!! 15.2 to low 14's on small bias ply tires. Dakota R/T's are pigs, and the 340 demon dusters got better mileage to boot LMAO
 
your right Dakota R/T are pigs that's point and yet they still do pretty good with magnum head
 
It's called 'ported 675 318 heads'
If you had an old hughes catalog....you would know that they do those heads as well and claim 270cfm full ported.

Yes just about all mopar heads have the potential, at least they did back then...
 
For anyone interested in reading what the Shaddy Dell Speed shop has to say about magnum heads should check this post out. There are as cast and ported magnum numbers and ported magnums compared to ported J, Edlbrock and Commando heads.

http://board.moparts.org/ubbthreads...=366847&page=1&view=collapsed&sb=5&o=&fpart=1

I find this quote from Shaddy Dell quite interesting;
"All I've ever heard about the R/T head is that it has a W-2 intake bowl in it. Well I'm here to tell you, these regular magnums are pretty damn good in their own right. Look at how nice my bowl is.... You can't do that with a J head without hitting water. As for R/T heads I don't see a huge advantage, if the bowl is the only difference. I guess I need one in my hands to know for sure. Hint hint...... "
 
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