LA318 Edelbrock Magnum v RHS LAX Heads

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lilredrooster

lilredrooster

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Currently at the cylinder head selection stage: Seeking advice/experiences/thoughts/comments on choosing/fitting/using either of these two cyl head options on a LA318 for fast street/strip application in a Dart/Valiant 4:10 gears (Currently Mild/Standard-ish 318. (Yes I know & appreciate a 340/360 motor is a step up, am sticking with my LA318, Thanks)

I like the Aluminium Edelbrock Magnum, 58cc Comb/Chamber (If accurate) could help boost the comp ratio?? (Happy to change over rocker gear if it proves to be the better head). Port speed/velocity maybe too much for 318??
2.02 Inlet Valves: Not sure about clearance with 318 bore size, actual clearance/interference with bore and valve shrouding issues??

I also like the Iron RHS/LAX, less drama with the rocker gear, but bigger Comb/Chamber 62cc not quite as much advantage as the Edel/Mags?? Choice of 2,02 or 1.92 Inlet Valves which may help with the port speed/velocity issues?? Again Not Sure about the actual clearance with the 2.02 Inlets & 318 Bore Size and the associated valve shrouding issues with both/either 2.02 or 1.92 Inlets??

Very Happy to listen and to learn, Many Thanks in advance for any/all comments.....
 
2.02 + 1.60 = 3.62 - 3.91= .29. Space between the valve is smaller than the .29. Much!
Valve shrouding is the least of your issue. Other companies don't mind it and there set ups are extremely shrouded by compare. But you have none to talk about.

Velocity? The next biggest non issue you have.

The choice is up to you. You all ready wrote out the pro's and con's to the heads. Price is all that is left to figure out.
 
I didn't know that you can buy heads at LAX... I've flown through there a couple times and didn't know I could get heads there.... :banghead:
 
No such thing as too much port velocity on a 318, or really any street engine for that matter. What's your budget? And what kind of pistons you got? Heads can always be milled to get the cc you want.

And i'm not a fan of Magnum-based heads unless they got shaft rockers and LA intake bolt pattern... and i have a set of Magnums on my 360 lol. EQ's are the way to go on a tight budget.
 
Like the Title Says: "LA318 Edelbrock Magnum v RHS LAX Heads"

No mention of "EQ Heads" or "Airports" in the thread title as I am not interested in either at this point in time........

Budget extends to either the Edelbrock Magnum head, or, the RHS LAX Head, not interested in changing pistons currently.....

No disrespect intended....

Many Thanks for the interest.......
 
Go with the Eddy's, it's just a lick over 22 kilo's off the nose of the car weight reduction, which never hurts. I think though not 100% positive, the iron RHS heads actually weigh more than the stock iron heads.

Something to think about..............
 
MOPEkidD-3 said:
No such thiWANT&Es too much port velocity on a 318, or really any street engine for that matter. What's your budget? And what kind of pistons you got? Heads can always be milled to get the cc you want.

And i'm not a fan of Magnum-based heads unless they got shaft rockers and LA intake bolt pattern... and i have a set of Magnums on my 360 lol. EQ's are the way to go on a tight budget.
Click to expand...

1.92 EQ heads.. They flow 240-ish with good valves,stock valve job out of the box. The combustion chamber advertised at 58 c.c. Eddy's are decent,looked at those for my Magnum. The E.Q.'s are a better deal,if you know the research ... Want ported?...
Contact Brian at I.M.M. engines (Indio ,California- U.S.A) /Mike at MRL Performance here/ FABO member RAMM here as well,by P.M.Describe your situation:(WHAT YOU REALLY WANT & EXPECT/and your complete combination).
 
Abodybomber said:
1.92 EQ heads.. They flow 240-ish with good valves,stock valve job out of the box. The combustion chamber advertised at 58 c.c. Eddy's are decent,looked at those for my Magnum. The E.Q.'s are a better deal,if you know the research ... Want ported?...
Contact Brian at I.M.M. engines (Indio ,California- U.S.A) /Mike at MRL Performance here/ FABO member RAMM here as well,by P.M.Describe your situation:(WHAT YOU REALLY WANT & EXPECT/and your complete combination).
Click to expand...

Oh yeah Tim i hear you loud and clear... but the OP doesn't like us talking about a 3rd option apparently lol

The lighter weight would be the only real reason i'd go with the Eddies since i ultimately want a cornering machine. Gotta buy them bare and have them prepped by a good shop unless you want stuff falling apart after 5000 miles... plenty of threads on here about that :pale:
 
Many Thanks for your thoughts and comments on this, very helpful and very much appreciated.......

Couple of things I wanted to bring up here:

The top end oiling system differences between the magnum & LA head versions:
Is one oiling system version superior to the other? Is it better to stick with the LA btm end and LA top end matching than have the mixed combo of the magnum top end oiling system with the LA btm end??

318 std low compression issues:
Whichever head I end up using, I am leaning towards skimming/machining of cyl heads to bring up the comp ratio, guessing going from approx. stdish 8/1 to a pump gas 9.75/1...
Anyone prepared to guess (approx) how much to mill off cyl heads?? plus, which head/heads would be best suited to this type/amount of machining??

Both of the above issues are going to help me greatly with my cylinder head choices.....
 
From 8.0-1 to 9.75-1?

LMAO! A LOT! .100+?!?!?!

Ether oiling system is fine so long as it gets the oil. There both prove in the street and on the track.
 
Any thoughts on the maximum/limits that can be typically/safely machined/milled from SBM 318 cylinder heads with a view to raising comp ratios???

Are there any particular SBM 318 cylinder heads "available" of "any type" that would be better suited to major/maximum machining/milling (as above) with a view to raising comp ratios???
 
In general you don't want to mill heads any more than you "need" to because it screws around with the rocker/pushrod geometry as well as the intake manifold mating surface. I learned that straight from my machinist who has 40+ years of experience. It can help give you a bit more (like 0.25 increase in comp. ratio) but for larger increases the proper way to do it is to get taller pistons. This is why I asked, what pistons do you have?? If they are stock or stock-replacement advertised at 8:1 comp then iron heads will be better.

As far as oiling goes, you can use Magnum heads on LA block (as long as you use hollow pushrods) but you can't use LA heads on a Magnum block. For your level of performance either LA or Magnum oiling methods will work fine. The main issue between the two types of heads is more about the strength of the individual rocker pedestals (Magnum, weaker) vs. single rocker shaft that distributes the load over 5 mounting points simultaneously (LA, stronger). Again at your level of power it's also not an issue either will work fine.
 
G`day M-Kid,

Grrrreat post, technically I totally agree with your post, in an ideal world, arguably, the 318 is probably not worth pursuing if you want to push the performance boundaries, at least from a financial point of view anyhoo......

In reality most of us are limited in one way or another due to various restraints, budget, knowledge, skillset, responsibilities, time, etc, etc...

I have seen many examples of 318 owners seeking performance gains and decking either blocks and/or heads up to 0.065", chasing compression, to some extent, technically you could argue against many/all performance upgrades...... Not suggesting milling is the best option, but it is an option...... In my case an option I would like to explore further......

Just chasing some actual milling/machining numbers that may have worked or (not worked), for people in the past.......
 
lilredrooster said:
Like the Title Says: "LA318 Edelbrock Magnum v RHS LAX Heads"

No mention of "EQ Heads" or "Airports" in the thread title as I am not interested in either at this point in time........

Budget extends to either the Edelbrock Magnum head, or, the RHS LAX Head, not interested in changing pistons currently.....

No disrespect intended....

Many Thanks for the interest.......
Click to expand...

I hear you loud and clear regarding the "EQ Heads" (just having a hard time staying quiet about them) but they're really worth taking a look at.

By the way, EQ stands for EngineQuest and they are a Magnum style head. They also cost less than both your options mentioned since you did mention budget.

The part number 318B (I believe) is drilled for an LA style intake. This is what I have on my engine. It was built by Brian of IMM Engines. It made 403 HP @ 5,500 RPM and 467 lbs (I believe) @ 4,500 RPM. I could be a little off. I will soon fire mine up in the Duster maybe this weekend.

The quick details are EQ Heads, CompCams XE268H cam, 9.6:1 CR, AirGap intake, CompCams roller rockers, Holley 750 CFM on a stock stroke 360.

Keep in mind, if you decide to go Magnum style head (any brand) then you need Magnum style rocker arms.

We don't want to confuse you or anything, but just want you to make an informed decision in order for you to get the most out of your money.

Here's my engine on the dyno and I attached a pic of it sitting in the Duster:

[ame="https://www.youtube.com/watch?v=Fqr-Af66XAI"]00153 - YouTube[/ame]
 

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Hey..
Not thread stealing because I feel this is relevant to some extent at least.

I am also bolting together a Mild LA 318 at present along similar lines i guess.
I am going with the LA style Edelbrock 60779 Alloy head but have stepped up to KB167 Hyper pistons and zero decked my block (which was barely a 0.010" cut).
These heads measure at 64cc (advertised as 63cc).

Even with this flat top piston change I will be lucky to get 9.5 Comp ratio because of the larger head chambers. With the alloy heads I really should be trying to achieve a minimum of 10-10.5 Comp ratio. Therefore I am now considering machining my heads to achieve say 10.1 Comp.

How much can you safely machine these alloy heads...? I am yet to find out.
I believe I would need to remove around 0.035" of material to achieve that 10.1 Comp.
Currently this cut is estimated only.

So... If you wish to stay with the stock style pistons (assumed?), you will definately struggle to gain a decent comp ratio unless you run the smaller head chamber size.
I'm not sure that taking 0.030" to 0.040" from an alloy head is the best way to go...though I am in currently contemplating this myself right now.

How much can you safely machined a set of heads.. Alloy heads?
Sorry, as yet I don't know. :evil3:

Cheers,
Teedog
 
Edelbrock lists the the deck thickness of their heads as 5/8" (0.625"). Seems to me like .040" off those heads is not a problem.....

To the OP, see if you can swing the $$ to put in better pistons, like the KB167's mentioned above.
 
Some Grrrrrrreat posts there, once again Many Thanks for your help/thoughts and comments, very much appreciated as always..........

Totally agree that these recent posts are definitely related and good value, also make very interesting reading, so please keep them coming.......

Like I said earlier, not out to offend anyone with any original/earlier comments........
 
lilredrooster said:
Some Grrrrrrreat posts there, once again Many Thanks for your help/thoughts and comments, very much appreciated as always..........

Totally agree that these recent posts are definitely related and good value, also make very interesting reading, so please keep them coming.......

Like I said earlier, not out to offend anyone with any original/earlier comments........
Click to expand...

No problem glad we could help, no offense taken :thumbup:

Teedog I don't know specific numbers but i think milling your heads that much would require the intake face to be milled a bit also. Hopefully one of our resident pro builders will chime in, this is a pretty heavily talked-about issue also i'm sure there are other existing threads on it. Try the forum search tool i'm gonna give it a whirl.
 
It costs quite a bit to have heads milled that much then to mill the intake side! Unless you know a guy.
 
Then in the future if you do want to stick them on a 340/360 you may have too small of a chamber.
 
you could swap in a set of magnum pistons which would get some more compression than take about .030 off the deck for more compression
 
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