Magnum vs LA bash!

[LXguy]

Magnum rockers are pedestal rather than stud. I think there's a lot made of that issue and it isn't really a problem for most people. I've spun mine to 6500 many times with the stock stuff without a problem. Its almost exactly the same thing as the 5.0 Mustangs run and they work fine there also.

Those same small vale stems don't seem to be hurting the Chevy LS engines any.

 

[K.O. SWINGER]

Must be. I always thought a smaller stem means a lighter valve which means less stress. But Im no engine builder and dont pretend to be,

Dont smaller stems flow better ?


Wonder why no one really make LA heads anymore if they are far superior ?

some of your best aftermarket heads are L A designed with small upgrades over the years and you can get them as nasty as you can afford:sad5:

 

[AdamR]

some of your best aftermarket heads are L A designed with small upgrades over the years and you can get them as nasty as you can afford:sad5:

Like what what beside the RPMs ? The Indy heads are copies of the old Batten W2s I believe. The Indy X heads are magnum based. B1s if they are still available are nothing like LAs. Mopar Performance only offers Edelbrocks that say Mopar on them and W2s now. The commandos are gone, The Magnum R/Ts are gone.

Im more into stock restorations or stock looking cars now so it doesnt matter to me which are better because chances are Im going to LAs but everything seems to be W2 based or Magnum based now so I dont know why they would do that if Las are better

 

[rumblefish360]

Its the fact you have to add those parts 5/16 valves, guides, locks, retainers. Thats a real world concern when building a budget motor.
I'm not a fan of the rocker setup, that was a step backward performance wise IMO. I don't believe the stability of said setup is as bad as many of us would think. If you consider all of those owners of those 380 HP 5.9 Magnum crate motors beating the piss out of them, you would think that if it was an issue it would be blabbed about all over the place. The Magnum head just doesn't lend itself well to high RPM duty anyway not enough cross section, I think most people will only turn them around 6K on average, because thats likely most mildly worked ones will run out of breath. As for improving the rocker setup, put in screw in studs, roller rockers, and a stud girdle. I think there are some outfits selling kits to do just this.

On a budget build, I see no issue as well. I'm thinking moderate to high HP applications. Lets start the moderate levels at 500 HP. While that may be a thumper for the street and have the Go-Nads to run well at the track, serious power level, absolute max effort builds is what I was thinking about. A bit more RPM than 6K.

I guess, in reality, valve train stability issues will be there with no matter what your run. Just less with the "LA" type set up and like you said, upgrading is needed over OE issue's.

For street/strip builds, like mostly seen here, I agree most often than not, best power is made and kept under 6500 anyway. And not many at 6500.

 

[AdamR]

anyone building an all out race car wouldnt being using Magnums or LA heads. They would likely be using W2s, Indy's or Edelbrocks.

 

[inkjunkie]

The B-1's are still available. They use a factory LA intake, they need stands but I believe they use oe style shafts & rockers.....

 

[bad440]

i dont like the pedastel rockers,too much valvetrain flex.then you end up having to buy stud girdles just like a chevy.i'll take the shaft rocker setup anytime.and next time my heads get done they will get 5/16 or 8 mm valves lighter is always better plus should pickup a little flow ...

 

[moper]

It's rare I agree with pretty much everything someone posts, especailly in multiple posts.. But I'm with Skrews. The Magnum benefits from modern design and engineering. The fact that the lower end (basic dimensions) has not been altered demonstrates the issues noted at the time of desgin were mostly top end. At least that's how I see it. Mopar is still behind technologically IMO but the Magnums were a huge step in the right direction, by employing the best new V-8 technology from the 80s in the 90s...lol.
All that being the case "engieering and design wise"... I still prefer the LA engines. I have no trouble making power with them, in stock, as cast, or ported cases. And the parts are readilly available and cheaper (cams, intake choices, pistons, flex plates/flywheels, etc...). Call it "comfort food" engine wise. But that's what I like and it still works for me.
Some others here are partial to LA stuff. I don't agree with all bench work that's posted but thats no big deal. Benches are not truth-tellers. Neither are dynos. The track is. With all the posts about basic Magnum combos, and after disecting a couple 300 and 380hp crate engines, the evidence is the Magnum engines make more power as factory delivered. It's not just the heads. It's the whole package as Skrews says. I'm also a firm believer that once an engine is torn down and is to be built for performance - core engine choice between Magnum or LA means very little and the LA-based stuff is much cheaper. So on builds you'll rarely see me say "run Magnum stuff".