318 heads

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That’s true.

For a mileage exercise, I’d just use the heads that are on the engine. I did say if I had a choice of ready to run heads on a table waiting for me to pick up and use, but the money involved……

I’ll just use what I have and do well with it. It really is about getting the cylinder efficiently filled up, burning all of the air/fuel, getting it out efficiently.

A stock valve head well prepared is all you’ll need to do to your heads.
 
I'm not super familier with stock SB heads, but if I were looking for milage from an LA, I'd be thinking of closed chamber, large valve heads, MSD ignition, small 450 to 500cfm 4bbl or 2 bbl and the cam would be a hydralic roller, wide LSA, bigger lift, lower duraton cam.
 
toolmanmike said:
I just need to walk out in my garage. I "had" 2 sets of Magnum heads with no cracks as well. The cracked stories give those heads a bad image.
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I've had a few sets of each that were not cracked, but I've seen more that were. So, there's something to the "story" I do believe. I'll put it this way, You can see a clear difference between say early to mid 70s LA heads and 302 and Magnum heads as for thickness. It's pretty apparent.
 
roccodart440 said:
I'm not super familier with stock SB heads, but if I were looking for milage from an LA, I'd be thinking of closed chamber, large valve heads, MSD ignition, small 450 to 500cfm 4bbl or 2 bbl and the cam would be a hydralic roller, wide LSA, bigger lift, lower duraton cam.
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Or go Slant 6. lol
 
In all seriousness, IF I wanted a Chrysler small block for mileage, I'd choose the early "supposedly" 9.2:1 318, blueprint it TO 9.2:1 because we all know they were actually much lower and build it stone stock with a thermoquad and some Summit headers. BAM, I just gave you the recipe for a 20 plus MPG small block. With ease.
 
RustyRatRod said:
I've had a few sets of each that were not cracked, but I've seen more that were. So, there's something to the "story" I do believe. I'll put it this way, You can see a clear difference between say early to mid 70s LA heads and 302 and Magnum heads as for thickness. It's pretty apparent.
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You can see a clear difference between say early to mid 70s LA heads and 302 and Magnum heads as for thickness. It's pretty apparent.[/QUOTE]

True that.
 
rumblefish360 said:
An example of mileage type of camshafts;

High Efficiency Hydraulic Flat Tappet Cam - Chrysler 273-360 245/255
Or
High Energy 206/206 Hydraulic Flat Cam for Chrysler 273-360

But I really suggest calling up a few cam grinders and asking for there help on what would most probably be a better cam for mileage than the ones I listed.
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I like the Voodoo high efficiency stuff. The problem would be that they would run so much better than stock, you'd have your foot in it all the time. There goes the mileage. But that'd probably be true of the stone stock motor with thermoquad and headers. Make no mistake, that would be a tire smokin sumbitch.
 
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LOL! Well, the increased torque is always welcomed and run for sure. It would be the main focus I think for getting the most out of the fuel for mileage. A&F easy in, easy out, all burnt up, yea, winner I think.

On my first ‘79 Magnum with a 360, I was able to get 20 mpg on the Hwy. Now I can get a good bit more out of my ‘15-1500 Ram.

Using basic mileage techniques, IMO, I did pretty OK.
A nice mileage getter was the MSD & a .055 plug gap at a low cruise speed for the multi spark advantage. Other than that, I used a 600 AFB on the factory intake with a trap door air cleaner. Dual exhaust off of the manifolds. 2.76 gears behind the 904. And easy on the Hwy speed.
I never got to headers, which may have helped. IDK though, maybe?
 
rumblefish360 said:
LOL! Well, the increased torque is always welcomed and run for sure. It would be the main focus I think for getting the most out of the fuel for mileage. A&F easy in, easy out, all burnt up, yea, winner I think.

On my first ‘79 Magnum with a 360, I was able to get 20 mpg on the Hwy. Now I can get a good bit more out of my ‘15-1500 Ram.

Using basic mileage techniques, IMO, I did pretty OK.
A nice mileage getter was the MSD & a .055 plug gap at a low cruise speed for the multi spark advantage. Other than that, I used a 600 AFB on the factory intake with a trap door air cleaner. Dual exhaust off of the manifolds. 2.76 gears behind the 904. And easy on the Hwy speed.
I never got to headers, which may have helped. IDK though, maybe?
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Yup. I think headers help mileage every single time. But you have to remember to get mileage, you gotta govern that right foot.
 
Heck yea! With my Magnum, I was trying to seek mileage as I was rush hour driving 25 miles one way to work then. In the day time stop and go crawling traffic to work/home, it was 16/17 mpg’s. During the trips to Richmond/Midlothian Va. & Winder Ga., it was a solid 20.
 
rumblefish360 said:
Heck yea! With my Magnum, I was trying to seek mileage as I was rush hour driving 25 miles one way to work then. In the day time stop and go crawling traffic to work/home, it was 16/17 mpg’s. During the trips to Richmond/Midlothian Va. & Winder Ga., it was a solid 20.
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What were you driving?
 
Mostly with a healthy motor ..the mileage is in your timing and drivetrain..as in tq convertor, gears...unless you're running too much carb for your driving style/conditions
 
If you’re really going for mileage, get a 239 LA or Magnum V6 to retrofit in and gear it with 2.18-2.45 gears for a fifth Avenue. I got one in a 90 dodge truck with a five speed and 3.90 gears and it’s begging for 3.21 or 2.94 gears. I can pull out in third gear. Mileage still goes over 20 during mild cruising.
 
toolmanmike said:
What were you driving?
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A ‘79 Dodge Magnum, 360, 904, 8-1/4 w/2.76 cogs, 235/60/15’s on all 4 corners. The following mods were done;
Trap door air cleaner (‘72-340)
Federal-Mougal 600 emission AFB all hooked up.
Dual exhaust @2-1/4 into twin high flow cats
(State law at the time, no way around it then)
With an H pipe into Thrush turbo mufflers exiting at the rear bumper.
A MSD 6 box and wires.
Recurved the distributor
 
RustyRatRod said:
In all seriousness, IF I wanted a Chrysler small block for mileage, I'd choose the early "supposedly" 9.2:1 318, blueprint it TO 9.2:1 because we all know they were actually much lower and build it stone stock with a thermoquad and some Summit headers. BAM, I just gave you the recipe for a 20 plus MPG small block. With ease.
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The "late" 318 LA roller engines are already pretty darn close to their advertised 9.2:1 and they already have 302 heads and a roller cam setup.
 
YY1 said:
The "late" 318 LA roller engines are already pretty darn close to their advertised 9.2:1 and they already have 302 heads and a roller cam setup.
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And also GOT the mileage I spoke of....and better!
 
Found an sp2p at a yard on an old dodge pickup. That's what's going in my dart.
20210924_174150.jpg
 
rumblefish360 said:
Use what ever head you have. If I had to choose from the verity of 318 heads ready to run on a table, it would be 302’s. Use a piston that can get you some good quench. That might be a problem with the various cc amount of the 318 heads. Generally there all a closed chamber.

The stock cam is good for mileage. If your going to move away from a stock cam, you could look into the aftermarket since they actually have cams under that listing, “Mileage Cams.”

There was a thread over on MoPars a good while back where a guy went down this path. He used a high compression 318 and really tweaked the crap out of to the tune of (IIRC) 32pmg’s. *I Think* an overdrive was used.
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They have hardened seats. (302s)

The pushrod holes are way bigger so your pushrods will never rub.

And the exhaust port exits are slightly larger than the LA open chamber heads too.
 
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