I have the interest if you have the free!?
Which head/combustion chamber is better for performance? Speed master aluminum LA or aftermarket magnum iron head?
- Thread starter StreetSleeper
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I’ll bet you do. Lol
StreetSleeper
Well-Known Member
My impression of an AJ response!:
Not sure where you want to compromise regarding fuel efficiency, performance, and budget -the first two categories move in the opposite direction.
Much of this is obvious but for review:
More gears in your transmission, with a steep first gear so you can run an axle gear closer to highway gears.
For example
Mopar 833 (2.66) with 3.73 rear= 9.9218
Tremec TKX 3.27 with a 3.0 rear= 9.81
Close in first gear launch yet the 3.0 axle with a .73 overdrive gear will get you that performance and fuel economy.
There is more to torque converter selection that I simply don’t know-perhaps the higher stall converters are less efficient than stock???
A999 904 autos come with a 2.75? First gear versus 2.45/2.48? Typical auto first gear-again am out of my element
My guess, smaller, more efficient intake runners (heads and intake), in comparison to engine displacement size, along with compression, and specific camshaft point towards fuel efficiency.
I don’t enough where air speed becomes too turbulent in these intake runners-the geniuses here would have to tell you where to draw the line with a 273/318/340/360/37X/408/416 etc.
So closed chambers should support more compression- so more fuel efficiency.
Fuel econ people run small carbs-again not in the direction of performance-how much performance or fuel economy do you want?
Cam intake lift at .050” at 204 starts the torque at 700 rpm (where yellow rose said don’t lower your engine idle any lower than that.) But no one here runs a cam that small (like 318willrun ‘s crane cams 693901 or 693902 cam/cam lifters) for performance unless (like 318willrun’s scenario of 2.45 gears) they are running highway gears
Some books like intake and exhaust valve sizes closer in size to each other for fuel efficiency .
Valve job seems to do as much as head porting-you get both Econ and performance with this.
Obviously:
Lighter car,
Wheel size that matches engine and cam size
There are hundreds of books on this broad trade off.
As RustyRatRod would say, “hit the books!”
Or maybe get a discertation from AJ as I just took a swing at performance versus gas mileage.
I don’t think doing anything that increases fuel air consumption will support economy-only improving efficiency of the process.
I think birdsong on YouTube got 20++ mpg with a 440+cubic inch B body with ?3.23? Gears
Someone can correct me on that.
Bert wishes
Yeah you got slant 6 heads to do. lol
Where’s that LOL button.
cookietruck
Well-Known Member
Then you want the aluminum heads.
EQ is back Parts - EQ Cores & Recycling
The Promaxx are new castings but they are just $200 cheaper than the Edelbrock Magnums ($1150). DODGE 5.9L/360 Mopar small block Magnum Cylinder Heads - Free Shipping on Orders Over $109 at Summit Racing
Engine Quest is back with the
I will be purchasing Performance Injection Service new EQ heads with Level 1 porting for my '98 Grand Cherokee 5.9. For a "max performance" build where iron was a requirement the Level 2 porting is much more extensive ($1900). Advertised to flow 212 cfm @ 300" lift. 290 cfm. @.500"+. SSR, deshroud, blend, pushrod, pinch, valve guide blending, competition valve job, ...
Mopar EQ Cylinder Heads
There's no one answer for this question, because it depends on the rest of the combination.
cookietruck
Well-Known Member
Those EQ heads aren’t the same castings as the old ones.
True, but it’s not relevant if you aren’t using them OOTB.
The current EQ heads are the 318 version of the old one. The 360 version didn’t return but that’s just what I have read. PIE can make the 318’s better than the 360’s.
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DionR
Well-Known Member
There is no such thing as a 5.2/318 vs. 5.9/360 head in the Magnum castings. They were the same head regardless of displacement. The factory never had a different casting like they did back in the LA days.
StreetSleeper
Well-Known Member
Can one assert that the stock magnum heads 5.2/5.9 are base level and then the R/T next level? Should the next level only be used for stroker builds?
How would that cast iron R/T head (intake runner 179cc -??) compare to the aluminum magnum head?
DionR
Well-Known Member
I want to say I have heard that the cast iron R/T's were better than the old EQ's which were better than OEM. So that is how I would rank them.
For a stroker build, I would guess even an R/T head would limit them without some work unless the cam was pretty mild.
For a stock stoke build, I would say the EQ's or R/T's would be fine depending on the cam.
For a stock Magnum build, I think even the current EQ's are fine as the cam is the bottleneck.
But I am not someone that would give advice on these things so they are just my guesses.
No real idea on that. If the Speedmaster is a ripoff of the Edelbrock aluminum head, I would guess the Speedmaster would have better ports. But complete speculation on my part.
With that cam any of the magnum style heads would work well. Even the stock magnum heads with a good valve job very minimal chamber and bowl work would be a good choice. Check out Charles Serviedo (spelling?) youtube videos about small block mopar heads.
Just to confuse matters even more, Edelbrock has both and LA casting and a magnum style casting that are very different.
Yes I have a set of x heads on my 340. 11.86 at about 3900 lbs. I built it to go 12.20's at 6000 and on my first run it went 12.20 at 6 grand. My friends were not amused.
Newbomb Turk
Well-Known Member
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I like you. already.
Too bad yur 2000 miles away.
The short answer is;
IDK the answer to this question.
But I can tell you that running over 190psi cylinder pressure, on 87E10, makes me a very happy streeter. I saved a lotta lotta money on running that cheap gas.
*********************************
The intermediate version is;
My combo is pretty much limited here in Manitoba to 65mph, 75 on certain parts of the TransCanada hwy, and when I come stateside, a lot of interstate traffic is doing 85, unless the occasional Corvette comes by@ 110plus.
Therefore, I set my car up tp be revved right out at ~60>65 in Second gear. Theoretically then, I just cammed it to hit the marks and until I do something with the Suspension, the car is traction limited, and I really can't ET any significantly better.
However, I really don't care how quick the car isn't.
The problem for me was cruizing.
To hit that 60@6000 mark with a 4-speed in Second gear, requires a rear gear of 4.10........ Even with a GVod, that is still 65= 2600, and there is no good mpg to come out at that rpm.
But the thing is, with my suspension, the tires are still spinning at 60mph, so I reasoned that the car won't be any slower if the tires are spinning at 6000 or at 7000
And that opened up a new world for me.
I installed a Commando 4-speed and 3.55s, and I bypassed the GVod ECU for split shifting.
Now I hit 60 @6400 in First-over, and for cruizing I get 65=2240 in GVod. So now, I just recammed it for that. See with an HO 360, you can do stuff like that. IDK how it wouldda turned out with a 318.
Caveat*1
>>One thing with a manual trans, that a guy has to be aware of is driving slow.
With the 4.30s that I was running with the 2.66 low, my slowest speed was 3.8@550
With my new 3.09 low and 3.55s, 550 rpm is 4mph. The only ways to drive slower are; to ride the brake, ride the clutch, or retard the timing. I chose timing and at 5*, now she runs 500@ 3.45mph.
Some of you guys might ask "why is this important?"
Well my answer is this, until you have the capability, you won't get it.
But once you hear your modest street-cam rumpity-rumping across the parking lot at 500rpm, then you'll get it. And following pretty women in a parade is just icing on the cake.
The long version.
As to fuel-economy;
IMO, cruizing at 2240, really has potential.
For one long distance trip, I set the car up, geared for 65=1600, which was 85@2100. I installed a specially prepped Holley 600, and I had my Cruize timing dialed in. The car went 32mpg on that trip, point to point, with a 223/230/110 cam pumping 195 psi.. Now, I know that some of you are gonna doubt that, that's your problem, yur not thinking outside the box. If your car only needs 35 hp to go 65mph, then just tune your car to make that, and the only difference between a 2.5 liter engine, and a 6 liter engine, making 35 hp, is internal friction. But while the 4-banger has to spin about 2200 to do it, obviously, the 6 literV8 has enough power at 1600. and in my case, even lower.
So before you start slinging mud, go ahead, build the combo and prove me wrong. Then you can get the facts. and BTW, the 600 Holley is a gashog, compared to some spreadbores.
The reason I talk about fuel economy
is because in the very near future, I believe the cost of gasoline is gonna skyrocket, as greed envelopes this old world of ours. Therefore, if we wish to continue to drive our 400 hp behemoths of yester year, it behooves us to modernize them, to get similar to 4-cylinder fuel economy.
I have over the last 20 years, developed a winning combo.
For those of you still running small-displacement, 8/1 iron-headed slugs with open chambers, with near 292 cams, and 3500+ stalls, and 4.30 gears ..... Your days are numbered.
IDK the answer for you.
But IMO; the one thing I believe, is that, the days of 3-speed autos and 4-speed manuals is rapidly drawing to an end.
As are long-period cams and,
and lo-pressure, open-chamber, iron heads are only days behind.
If you are presently building an old-school combo like that, it won't be very long until the car will be a Saturday afternoon only car, and not long afterward, she will be up on blocks; I believe that. This is especially true as most of us are pushing retirement years, and will be on fixed incomes soon.
So here is my recipe, for the coming age.
NUMBER ONE thing is to get an overdrive, and a decently low starter gear . You need to get the hiway rpm down. And I very highly recommend a manual trans, so that you can get rid of the highstall convertor. They say that convertor is costing a DD at least 2mpg. IDK if that is true, as I have never tried it.
Then, after the chassis has been determined, only now should you begin to discuss the engine.
To that end;
I have had good success with a small block with very hi-pressure closed-chamber alloy heads, and Very tight quench flat top pistons. with adequate ring-gaps and notta chance would I run lo-tension rings on the street. and My next cam will be a modest solid lifter flat-tappet cam and I will send some oil directly to the lobes, so that I can continue to rev the beotch with hi-pressure springs, to not lose control, and the lobes yet live. I will need a custom cam, no doubt.
I run a hi-volume oil-pump so I can leak some oil to various important places that will otherwise die at idle of 500 rpm. and of course, I run a hi-capacity oilpan if for no other reason than oil-cooling.
That's the basic plan. After that, the bolt-ons are same as usual.
The last page
What cam?
Well, that's tough; I haven't seen an off-the-shelf grind that interests me.
But two things I already know; Since I will be targeting ~195psi, and I know the Scr will come in at around 11.3 with a 6liter, this already sets the Ica at 60 to 64 degrees. And Ima thinking I want an LSA of 107 or less., and I want a longer than might be considered normal, power stroke, for fuel-economy. The rest is up for grabs, but with direct lobe oiling, I'm thinking a high energy design (not a Comp. Hi-Energy), is what I'll be asking for.
and BTW, knowing what I now know, 430 hp is NOT on my horizon. Ima thinking 300 will be more than adequate. I'm even considering a 318LA, yes it's tru, considering.
Here's a hypothetical cam I'm considering.
226/232/107 hi-lift this is 050 net after lashing.
At zero-lash this might be 272/280/110 and if it was, then
Ica would be ~62*, the Powerstroke would be ~112, and overlap might be ~62*
I could get some serious MPGS out of that 112*Powerstroke, if I can just make that 62 overlap behave at 2200.; that's gonna be the trick. But I got some ideas.
Meh, I might have to downsize a lil. The problem with downsizing is now the cylinder pressure goes up, and I'll have to reduce the Scr to less than 11.3. No biggie, we have the technology.
I have time this winter to play the numbers game.
I even have a couple of 340s I could choose from. Yeah 22 cubes would flesh out the bottom end just about right.
Different variation on this question
What head would be better for a work truck, that is also an occasional tow pig?
Full bed to capacity about half the time, daily driver all the time? .
Assume the short block to be built up the same, only with different choices of heads to top it.
I'm thinking iron.
What head would be better for a work truck, that is also an occasional tow pig?
Full bed to capacity about half the time, daily driver all the time? .
Assume the short block to be built up the same, only with different choices of heads to top it.
I'm thinking iron.
33IMP
Well-Known Member
To quote the o.p. in post #1, which head for a MAX performance build" ?(capitals added).
For a motor with 14 to one compression, a .750 solid roller motor, with two 850s on a tunnel ram, and 471 cu inches, id probably use the speedmasters if those were my only two choices.
Anything short of a MAX performance build, a different answer may apply.
For a motor with 14 to one compression, a .750 solid roller motor, with two 850s on a tunnel ram, and 471 cu inches, id probably use the speedmasters if those were my only two choices.
Anything short of a MAX performance build, a different answer may apply.
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