Aluminum heads

[AJ]

Has anyone used the Mopar Performance aluminum heads #P4876311 ? The MP tech line claims with some good porting they will flow better than the Stage 5's or Stage 6's fully ported. I would like more info on these heads if anyone knows about them. I am considering them for my drag car. Thanks, AJ

[gsmopar]

I'm not sure if those are the same heads, but MOPAR did a article on them a couple of monts back (al-stock replacement heads???). I'll try to dig up the article for you. Any how, they did a crap load of port work in the article and the flow numbers barely got better than the EB heads out of the box.

Later,

Greg

[DartGT66]

At around 800$ each empty the price is insane compared to the E-brocks.

[AJ]

GSMOPAR thanks, I sure would like that info. The reason I am not looking at the Edelbrocks is that I have custom headers for my car and they would have to be modified because of the raised exhaust ports. And as far as the price--that has come down also.

[DartGT66]

If I have not completely misunderstood, that aluminum head has the same exhaust port as the stage VI's, and that is raised about 1/4" more than the Edelbrocks exhaust ports. The Edelbrocks have 1/8" raised exhaust ports according to the information I have.

[AJ]

DartGT66, thanks for the info-but- the guy at Mopar Performance tech line told me that their aluminum head P4876311 has the exhaust ports in the same location as a stock 906 head. If anyone know this is incorrect--PLEASE let me know. AJ

[ehostler]

You should be able to bolt those headers up to either head, as the exhaust ports are in the factory locations. The exhaust floor differences are further into the head, beyond the port.

[AJ]

ehostler, I don't understand what you mean by-- "You should be able to bolt those headers up to either head, as the exhaust ports are in the factory locations." Do you mean the 906's and the P4876311's? Also, do you know much about the P4876311's? Do the exhaust mounting holes go into the water passages like the 906's? Are these good performance heads? Thanks, AJ

[ehostler]

Everything that I have read says that headers for the 906/452 heads will bolt right up to the P4876311 heads or the EB heads, as the exhaust ports are in the exact same locations. I know that the exhaust studs are dry in the EB heads. I'm not sure about the P4876311 heads.

[Doug Wilson]

If your headers fit one, they'll fit the other.

[AJ]

I thought that the Edelbrock aluminum heads had raised exhaust ports---so that would raise where the headers mount.

[timty2]

In theroy, you could bolt up your stock exhaust manifolds to these heads (Although I do not know why you would want to!)

Ports are in "Factory" locations.

[moeflo]

AJ, did a mild, but full port on a set of these for a bracket car. The owner works at a mopar dealer and got a good "back-door" deal. They are a sturdy casting, although the valve-heights were off(variance of .030"). Flowed one out-of-the-box, good vs. 452's etc, at 279 at .700'. Only checked one hole,. Finished them up at 317 to 320 at .700". And this wouldn't be considered a budget port-job. Not an, all-out development-job, either. They are going on a bracket car with a .650" gross roller cm. I'll let you know how they turn out.

But they suffer the stock valve-length curse, and I wouldn't expect a ton more from them, no matter how much effort was put into them

Without having flogged any edelbrocks, i'd venture to guess they'd be good competition for them IF they were the same price. But, at last check, they aren't.

The push-rod X-section, was opened to around 2.76 sq-in. (raisied roof, dropped floor, .080" push-rod wall thickness) A good street size, but small for a bracket car. You'll rely on some extra duration to get the torque RPM where you'll want it, if it's for a race-only deal.

Exh finished up in the 74% range

I think you'd be a bit to the good with the EB, if you're runing out of the box. I've also grown to hate a 3/8th valve stem, cause they weigh a ton.

[gsmopar]

Page 58 of the October 2002 issue of Mopar Muscle:

"MP's #P4876311 aluminum replacment big-block heads..."

Here is what they did with each test:

T1 - Out of the box 383/440 aluminum replacement head
T2 - Precision Serdi "race" valve job by Roger "Dr. Air" Helgesen
T3 - Minimal bowl blend of machined throat cut to bowl
T4 - Mild short side radius blend
T5 - Pocket port bowl, guide boss, and adjacent roof areas
T6 - Enlarge port runner, pushrod pinch, and scoop out roof within gasket and spring seat constraints
T7 - More involved short side turn rework. Laid back and rolled shape
T8 - Cut floor hump (ramp) significantly, again revise short side turn
T9 - Enlarge roof to port entrance .300 inches above stock gasket line
T10 Polish Port

Here is the flow at .600 in (same lift the eb's are rated):

T1 - 263
T2 - 254
T3 - 269
T4 - 278
T5 - 280
T6 - 284
T7 - 292 (Same flow as EB for a lot more $$$)
T8 - 297
T9 - 302
T10 - 305

This article is what made me buy EB heads!

Good luck,

Greg

ps: Moeflo does good work! The best these guys got was 308 at .700 in!

pss: My only concern with the EB's and custom headers would be the angle plugs. I can email you pics of mine once I get the headers bolted up (hooker super comps 2" primaries).

[AJ]

Thanks for all the info guys. The EB's sound good out of the box-but I am still concerned about the fit. GSmopar- let me know how yours fit. My headers have 2.5" primary tubes. Moeflo--where are you located, and what do you charge for porting work? (you seem to know what you are doing)

[Doug Wilson]

If your headers fit a modified (or stock) iron head, then they will fit the Edelbrock head - absolutely.

What is it you have heard or read that makes you so sure that they won't fit?

My small block Ed. heads bolted up to my MP fenderwell exiit headers with exactly ZERO problems. I will be buying the big block Ed. heads for my 440, and will be using Jet-Hot coated Hedman headers.

[ajmopar]

2.5" primaries?!!! Oh my, that's huge.

[moeflo]

AJ, get the EB's. Like Doug, and others said, your headers will fit. The Mopars exh openings are a tick higher than stock also, but these slight differences can fall into sagging motor mounts, production tolerences, etc. You won't have any more problems, than if you were using stockers.

The EB's , as a "out-of-the-box" item, don't have any serious competition, when the flow increase,installation issues, cost, are considered. That's why these heads are selling. Finally a good bolt-on piece, for a Dodge.

gsmopar, appreciate the kind words(check's in the mail)