commando's vs. eddie rpm's

-
S

stroker mike

Well-Known Member
Joined
Jan 21, 2007
Messages
336
Reaction score
0
Location
San Jose, CA
I would like to find out what you guys think of the commando aluminum heads by MP as opposed to eddie rpm's. Different chamber sizes, different intake cfm, wonder if they might not be better for a small cube hot rod, asopposed to eddies with bigger ports, might have same velocity problems as j and x heads on 318- am I wrong? Similar price range. My car ain't a race car, might be quick but it's a driver. Would the commando's give me better street performance?
 
I just looked at those on a Mopar website. Are they priced singly or by the pair. The description didn't say one way or the other. The price I came up with is fine if it's a pair, but if it's per head a pair would cost over $2300 plus shipping.
 
I like the Eddies but yes they are better.....especially the large port ones. OOTB the large port commandos probably flow as good as a set of fully done Eddies. Does MP still offer the small port comando heads?
 
I would say they would be more compairable to the Eddy's and the large port say the Race w2's.
 
they offer them - do they have them? otherwise it is kind of a mute point.
 
The commandos come bare, when you add up what it'll cost to complete them,ie:valves,springs,retainers and the fact they use w5 rocker gear according to the website,and they'll probably need work out of the box i'll bet the casting will need work,they are more then my ported Edelbrocks..are they better i don't know but i'm not complaining about the performance i'm getting from my Edelbrocks..:thumbup::thumbup:
 
Commando's are a well kept secret!Probably on a par with W2 heads.Large port version will flow well over 300 cfm when ported.
 
Stroker mike,you have no mentiono of rpm you intend to shift at or run at,or the engine size,tranny, gears,weight,etc.Both sets of heads can be worthless if you never intend to run the motor past 6000rpm,then you just rework the stock J heads/X heads.How big of a cam do you intend to use,over 525 lift and how much duration?Its no use buying these heads if you run a low lift cam,as most after market heads are making there power from 5-600 lift and turning the motor at 7500rpm.Its best to bobby jeosph at 1-770-443-8874,mrmopartech
 
well, I intend to have a light weight, quick clean and thoroughly bad *** car when I'm done. I want the weight savings of aluminum heads, I want to increase velocity at lower rpm's I want the smaller chambers, with the corresponding increase in compression and the added benifit of being able to run 10.5-11:1 compression on pump gas with no detonation, all in a 318 with a xe275hl street cam! They aren't worthless to me, I had also considered the aluminum magnums. My car is a 68 cuda, and I will have kb 167's in it, forged crank, stock hd rods, 2500 stall, rpm airgap, possibly even efi. I don't think it will be living at 5000+ TOO often, he he, but you take my meaning. I don't want to run large port heads, for my application it would be a waste, I have j heads that run fine. that is why I was pleased to see small port commando's with 60cc chambers. even if I run a 3.59 stroke I would still benifit. I think I want a quality aluminum head, good velocity, smaller chambers, good flow, in my street car. Make sense to you? It does to me, My 318 right now has 8.5-8.8:1, if I'm lucky. Why mill a perfectly good set of j heads down .040-.060 to increase cr when I would be ruining them for my next 340 or 360? Now, I am only speaking for myself, I certainly have my own perspective, and to those with ton's more experience than I, I digress, and with all due respect. I want my cuda to be as frikkin awesome as I can possibly make it, and still be a driver. But not a race car, I live too far from the track to be serious about that.
 
Stroker Mike,
My .02 is that the eddies and the small port commandos will be too large for the 318 CI engine. The eddies are 168 cc's and the small port commandos are 175 or so cc's OOTB, both of which are too big for the small engine. A 318 can't use more than 150 cc's max and flow 245 cfm's with a 1.88 intake valve, which this is a stock 360 head unported but they won't flow this well in stock form so the port volume go's up and becomes a hinderence, loss of velocity. A good 318 needs and can use a 302 head fully ported which should end up at 136 cc's and flow 230+ cfm's with a 1.78 intake valve. This type of head will make more power than the larger heads and you'll have more fun with the car. These heads will be more efficient than the eddies or the commandos for the 318 CI engine.
Now if your going to make a 349 style engine then the need for better heads becomes greater but still not as large as the eddies or the commandos.
My 404 CI Big Block needs 196 CC's of port volume but I run 184 CC's of port volume, why you may ask. Well the port velocity is better at 184 than it would be at 196, so I opted for the lesser heads and the engine runs 1.46 60 ft. times and 7.05 @ 102 mph at 2865 lbs. 1/8 mi.
The gain was .1 in 60 ft. and .3 in et over a large ported head, and the mph went up 4 mph.
Hope I'm not confuseing you but clairifing things a bit. Bigger isn't always better and being conservative in cylinder heads and having the right cc head for the engine without being too large is best.
Things that most do is over head and over carb. and over cam a engine. But as I said this is just my .02 worth.
 
Mike,
They would be too large also as they are listed in the Mopar Performance book as 177 cc's and with 1.92 intake valves, and that they flow 222 cfms. IMO these are larger than the eddies and equal to the small port commandos, the problem with these is the fact that you'll have to use all the magnum rocker gear, and intake manifold. You'll also have to change the lifters to have oil thru so the rockers will be oiled.
All the heads in the MP book are too large for use on a street type 318, or mild bracket race type engine. This is why I said that the 302 heads would be best, then a alternative would be the stock 340-360 1.88 valve heads, but it's just as I stated before that the heads are larger than the 318 engine will be able to use, and port velocity will be weaker and the engine will be down on power some, 30-40 HP.
We generally use a small port high velocity head on a 360's with large type race cams as the cam kills the amount of suction that the engine will be able to pull (loss of engine vacuum and signal due to duration of the cam and centerlines) and the heads help to make the cam work better, and create more signal from the cylinders, due to the small size of the intake runner. It's kind of like a small super charging effect. The 302 heads are good to about 375 RWHP when done properly and cammed correctly.
 
My .02, I think the best option would be the aluminum Magnums. Small chamber, not too large a port, and able to keep the power up past 6K. I think for a fairly mild 318, anything more is going to feal sluggish down low.
 
I don't know as much as some others but my OOTB Eddies on my 318 feel just fine down low and I only have around 9.5:1 CR.....if I had another point I'm sure it would be even better.
 
moper said:
My .02, I think the best option would be the aluminum Magnums. Small chamber, not too large a port, and able to keep the power up past 6K. I think for a fairly mild 318, anything more is going to feal sluggish down low.
Click to expand...

But the port size is the same as the commandos, and stroker even said that he wasn't going to be going over 5000 rpm's too often, so why would he be in need of such a large runner head. Is it because of the material they are made of and they would be neet to have.
I don't understand why you would put a head on a engine that is capable of 8500 + RPM's and then turn it 5000 a time or two. Now if he was going to build a 408 then the head would be fine and more useable to the rpms of the engine, but IMO it's way too large.
 
Dusterb318 said:
I don't know as much as some others but my OOTB Eddies on my 318 feel just fine down low and I only have around 9.5:1 CR.....if I had another point I'm sure it would be even better.
Click to expand...

Just think that if you had a smaller runner head that was built properly for your engine, that the power that the engine would make. You wouldn't need NOS to run 11.80's you would be running faster with out it and on pump gas. And you really need to be up around 11.5:1 compression ratio to make the aluminum heads work properly, due to heat dissapation. Also the larger the runner the more fuel is consumed, something thats not wanted for street use.
 
I agree I need more compression.....one of those things if I knew then what I know now I would have done it differently and bought different pistons.....but the motor runs for what it is. As far as the heat dissapation theory....I have been doing a lot of reading on that and it seems there is a consensus out there that is BS now with the types of aluminum being used for heads now. They have more density and are holding the heat in like the cast iron heads. Heard anything about?
 
If you know much about metal, that is a thing your not going to see in reality. If you need to hold in heat and run a light head for total weight reduction, theres polishing and coatings to help in this area.

You can make metal denser by the way it is cooled. How fast it is cooled.
 
Actually they are using different alloy's and they make the deck surface of the heads thicker to make them sturdier, as for the rest of the head they are still casted about the same as they were, about 3/16 thick and thats it. Alot depends on who casted them and what grade of material that they used, factory casting are thin and crack with regularity, from the eddies that I seen they are thin in spots and pourious and don't weld very good. Then there are Brodix and others that are high grade material and thick for porting, but as the old addiage go's you get what you pay for. I'd rather spend $1,800-$2,500 on a good set of heads that will be around for along time then have to spend the money twice and do the work twice. The high grade heads are 1/2-5/8 thick in the decks, and race only heads are 3/4-1" thick in the decks on big blocks, but they are also $2,500 each bare. But were getting off track here.
Will aluminum heads work, sure they will but will they be efficient and be the best for the job intended I seriously doubt it. Then you have to put a cost on them for the job performed, IMO weather you use eddies or commandos or magnums, figure out the cost and what your trying to achieve and see if it's feasiable. I just don't see spending $1,500.00 by the time it's all said and done (minimum)to turn a engine 5,000 rpm's a time or two. When a set of good stock castings can and will do the same job for less. But I'm not the one spending the $$$$ so it's up to the end user as to what they want and do.
 
The edelbrock head is not too big for a 318. This much I know.
Brian
immengines.com
 
Just a differnece of opinion BJR, nothing more. I dont think they are too big. Apparently there one or two who also dont think they are a problem. I know there are guys that can't ge the numbers you do with that setup. I tend to think more in a "not everyone can do that" mind set. The heat thing isnt BS. But, I think in a lot of cases, there's so much concentration on it that it becomes larger in the scope of things than really it needs to. For instance...I like to build tight quench engines. It makes no difference to me if it's iron of aluminun. So long as the distances are right. I'll run a dish if I have to witha quench pad to get it. If you reduce the area the heat is focussed on (small, tight chamber) you will inevitable keep more heat in the chamber, making more power. Also, the outer reaches of the chamber will not get as hot, or transmit as much heat away because of this. A good quench engine has little soot or markings on the quench pad or matching chamber quench area. That's because when the biggest heat is produced, there isnt much there to burn, thus it stays cooler. Now, if you build a large bore low compression enigne with no thought to quench, then the whole chamber (or much more as a percentage anyway) will be exposed to, and transmit heat away from, the chamber. That's when you want the extra point or whatever. I love the Magnum small chambers, and I have milled big block RPM heads to get them smaller and keep the distances right.
 
You must log in or register to reply here.
-

Back
Top