1978 318 heads? Small port? Or large

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That's all I have to go by Rusty. Books like this I read and learn from. Mr Shepard has made mistakes I'm sure as we all have. He has gathered information from greats like Tom Hoover, Jim Szilagyi,Bob Glidden, Keith Black, Ray Barton, Ted Spehar and dozens more. I don't need to get into a discussion about whether Larry Shepard knows anything or not. I just quoted what I had read. We can all draw our own conclusions and form our own beliefs. Mike
 
I know. But I have a TON of experience tearing engines down and that era is where I have the most experience. I have torn down I KNOW in excess of 1500 engines.

Never ONE TIME have I torn down a 318 that was a factory four barrel that had the big port heads. Not ONE.

Of course, that's just one little peon in Georgia. But I have never seen another one, read of another one or known anybody else that had big port heads on a 318 from the factory. So my experience is all I have to go on.

I KNOW this much. Chrysler most certainly DID put the 360 4 barrel intake and carburetor on the 318 engines with small port heads......which begs the question, if they did that, (and they DID) why in the world would they have done it both ways?
 
RustyRatRod said:
Negative. Chrysler never used the 360 port size heads on the 318. Not even on 318 police cars. They simply slapped the 360 4 barrel intakes on them.
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For 318 Quadrajet or Thermoquad police cars with the 360 intake and the ELB or E48 code on the fender tag?

That obviously applies to trucks and vans with different codings though. Every person I've talked to who took apart an original motor had 360 cast # heads to show for it. Never had one myself, wouldn't mind to but don't care. There even seem to be certain casting 360 heads that the 318s usually got that overlap with lower performance 360s that had IIRC had higher factory compression ratios than the performance motors.

Some of those vehicles with those 360 cast heads were also fairly low miles. The factory's even got the compression ratios listed for the 318 4 barrel motors- they were all down where the 360s were instead of where the 2bbl motors were. How did they drop .2-.4:1 with the same heads and pistons?
 
That's the thing. Those big port 318s would have had WAY under 8:1 compression. Not too spiffy for a police car.

Like I said........I am just speaking from what I have seen. I am quite sure that's not the end all be all.

One thing I have learned with Chrysler is to never say never.......but that's kinda tough to do when you never seen it.
 
Thanks for all the debate and knowledge guys. I would gather that no matter if and when the 318's did or did not have 360heads......my smog 1978 with a 2 bbl has small heads. Just didnt want to buy a 1k efi system to set it on top of an edelbrock performer with the goofy uni-flange. Anything made for the 360 woukd be a pretty big port mismatch I imagine. Maybe I will yank it altogether, maybe I will look for a weiand. We'll see. Thanks again
 
My Son's first vehicle was a 1983 W150 4X4 with a factory 318-4V. I still have the heads. They are small port 318 smog heads with slightly bigger valves. Happy to provide pictures to settle all arguments.
 
I'm with Rusty on this. I believe that the 318 4 bbls from the factory had the standard 318 asmall port heads and the 360 intakes...

IF they would have used the 360 large port heads on them, they would have had to install better compression pistons to get the compression up...
 
krazykuda said:
IF they would have used the 360 large port heads on them, they would have had to install better compression pistons to get the compression up...
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Why would they have needed to? The E58s had lower compression than the low-performance 360s and made more power, so why would losing compression in the 318s to gain power be a bad thing? No they didn't go all the way below 8:1 since they didn't use the thick gaskets that go in most rebuilds today, but they did get lower. In the later '70s it seems there were at least two chamber volume 360 heads- 318s got the smaller of the two like the low-performance 360s and the high-performance motors got the larger of the two. (like in the LREs and Super Coupes)

70dart340 said:
My Son's first vehicle was a 1983 W150 4X4 with a factory 318-4V. I still have the heads. They are small port 318 smog heads with slightly bigger valves. Happy to provide pictures to settle all arguments.
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Sounds interesting, I'd be intrigued to see pics or even just get the cast number off them.
 
Never too old to learn something. I never knew 318 came with a 4bbl. Always thought I was looking at 360's I guess. Thanks.:burnout:MT
 
Yes sir, they sure did. And they came with TWO different type of four barrel carburetors. The Thermoquad, of course and the Rochester Quadrajet.
 
A lot of the aftermarket companies make a port size "somewhere" between the two port sizes, so they work on either.
 
johnnymac2k6 said:
so to throw some fuel on the fire...Why do manifold companies market the intakes like this ? 318-340-360? is it just assumed the port mismatch isn't That bad?

http://professional-products.com/in...lock-mopar-v8-crosswind-intake-manifold-satin

i have a used one of these lying around...
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Yes. It's typically believed despite the hard push people make for port matching that small port intakes on large port heads are acceptable for economy and large port intake on small port heads are acceptable for performance.

RustyRatRod said:
Yes sir, they sure did. And they came with TWO different type of four barrel carburetors. The Thermoquad, of course and the Rochester Quadrajet.
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And 1984 was the last year for Tquads. Trucks very rarely had leanburn and I've not seen it on V8s beside 2bbls. Every 360 truck after 1983 had a Thermoquad or a Quadrajet depending on the year and every one I've seen had electronic ignition like the old cars.
 
RustyRatRod said:
I know. But I have a TON of experience tearing engines down and that era is where I have the most experience. I have torn down I KNOW in excess of 1500 engines.

Never ONE TIME have I torn down a 318 that was a factory four barrel that had the big port heads. Not ONE.

Of course, that's just one little peon in Georgia. But I have never seen another one, read of another one or known anybody else that had big port heads on a 318 from the factory. So my experience is all I have to go on.

I KNOW this much. Chrysler most certainly DID put the 360 4 barrel intake and carburetor on the 318 engines with small port heads......which begs the question, if they did that, (and they DID) why in the world would they have done it both ways?
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You know rusty, I don't remember for sure if I ever tore down a 318 factory 4 barrel engine, although I THINK I did 20 some years ago....and I THOUGHT it had 360 heads on it, but whos to say they were factory installed? I seem to remember reading somewhere that some of them had 360 heads, but that could have been incorrect. Sure cant believe everything you read, that's for sure!
 
johnnymac2k6 said:
so to throw some fuel on the fire...Why do manifold companies market the intakes like this ? 318-340-360? is it just assumed the port mismatch isn't That bad?

http://professional-products.com/in...lock-mopar-v8-crosswind-intake-manifold-satin

i have a used one of these lying around...
Click to expand...


The port size is nice if you can match it, but not necessary. The engine will run either way, but it will just sacrifice a few horsepower.

The manifolds will physically fit, so they can market them for all of the small blocks.

If you really want to port match, and have mis-matched head and intake, you can always get a carbide burr and gasket match them. Problem solved....
 
Thanks all, pretty novice question from someone with a 600+ hp 408 I know.lol i just wanted to get my facts stright before i either choked out this smog 318 with an air gap equilivent, and it was a complete waste of time. Or if it would work. really didn't want to have to pull the engine to gain 5hp via a gasket match. IDK if i'm bold enough to stuff some grease and paper towel down the port and do it with the engine in the car, probably a pretty dumb idea. trying to talk the drag racer in my head into just leaving this a reliable driver, and leaving the 318. i just really didn't want limited to that uni-flange performer. The fitech kit looks pretty viable, and i can eliminate all the hacked wires someone left me from the beautiful lean burn system.
 
johnnymac2k6 said:
Thanks all, pretty novice question from someone with a 600+ hp 408 I know.lol i just wanted to get my facts stright before i either choked out this smog 318 with an air gap equilivent, and it was a complete waste of time. Or if it would work. really didn't want to have to pull the engine to gain 5hp via a gasket match. IDK if i'm bold enough to stuff some grease and paper towel down the port and do it with the engine in the car, probably a pretty dumb idea. trying to talk the drag racer in my head into just leaving this a reliable driver, and leaving the 318. i just really didn't want limited to that uni-flange performer. The fitech kit looks pretty viable, and i can eliminate all the hacked wires someone left me from the beautiful lean burn system.
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I think even without gasket matching most large port intakes are an improvement over the Performer, but the small port heads are a pretty big limitation. I know people will say you can spend money on them, but to me that's reasonable on the 360 heads since I don't think I've lost money on 1 yet, but with the 318 heads it doesn't make sense. 360 head motors with a decent cam are respectable even with low CR- the small port motors I've never been impressed with before.

Anyway, since you're talking about FI- I'd think about putting a Magnum into that car to drive it. Just looked on your other thread- late '70s Fury, right? I have less in my EFI conversion than any of those kits, but I sure wish I'd had the sense to just get a whole donor, next time I will.
 
Infecteddog said:
I think even without gasket matching most large port intakes are an improvement over the Performer, but the small port heads are a pretty big limitation. I know people will say you can spend money on them, but to me that's reasonable on the 360 heads since I don't think I've lost money on 1 yet, but with the 318 heads it doesn't make sense. 360 head motors with a decent cam are respectable even with low CR- the small port motors I've never been impressed with before.

Anyway, since you're talking about FI- I'd think about putting a Magnum into that car to drive it. Just looked on your other thread- late '70s Fury, right? I have less in my EFI conversion than any of those kits, but I sure wish I'd had the sense to just get a whole donor, next time I will.
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78 monaco, which is the sister model to the fury, and cousin to the charger/cordoba/magnum.

I know very little about tuning EFI...so figured the intrigue of a drop on and self tuning efi kit (that can also control timing) was a neat idea. kills alot of birds with one stone on these old mopars...iffy factory ignition, the remnants of the lean burn garbage, and a 60lb cast iron intake manifold with a chokey 2 bbl... nothing too positive about any of that. so hence my desire to get a true 4bbl 4150 flange on it, w/o killing the bank, or the little power this barge has lol
 
johnnymac2k6 said:
This should be simple enough for some of you more versed in 318's than I. Some of you may have seen my other post about picking up a 78 dodge with a 318 and a 2 bbl. Was there a changeover year where all L.A. engines had the same 360 port heads? Despite 2bbl or 4? Or because this hog had a 2 barrel does it automatically have small port intake ports? Reason being im contemplating a 4 bbl intake, and want it port marched. But if its small port heads, im probably yanking it altogether as im not wasting the money on an edelbrock performer to put the planned efi (4150 flange) efi tb on.
Probably an ironic post as im not looking for power, just a cruiser, but I hate the uni-flange spread/square bore non performance intakes that sometimes even require the adapter plate.
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1978

The 318/155 HP {4-Barrel} > did come through with the same Intake Manifold as
the 360.

Also, the 318/155 HP {4-Barrel} came through with 1.88" Intake and 1.60" Exhaust Valve Cylinder Heads.

The 318 {2-Barrel} was a small-port Cylinder Head only.
 
Infecteddog said:
Why would they have needed to? The E58s had lower compression than the low-performance 360s and made more power, so why would losing compression in the 318s to gain power be a bad thing? No they didn't go all the way below 8:1 since they didn't use the thick gaskets that go in most rebuilds today, but they did get lower. In the later '70s it seems there were at least two chamber volume 360 heads- 318s got the smaller of the two like the low-performance 360s and the high-performance motors got the larger of the two. (like in the LREs and Super Coupes)


Sounds interesting, I'd be intrigued to see pics or even just get the cast number off them.
Click to expand...


Because a set of 360 heads on a 72 318 ended up at 7.6:1 compression...

Too low for me...
 
krazykuda said:
Because a set of 360 heads on a 72 318 ended up at 7.6:1 compression...

Too low for me...
Click to expand...

Well that poor kid in the thread the other day with the reman 318 was getting told left and right his 7.1 cr was great lol. Im with ya. Unless im hanging a few turbo's off the front nothing iron headed would be purpose built by me that didnt start with a 9 or 10.
 
1978 Specifications {California}

318/155 HP ~ 4-Barrel
* Intake Manifold ........ #4095080
* Intake Valves ........... 1.88"
* Exhaust Valves ......... 1.60"
* Cylinder Head ........... 65.5 CC
* Compression Ratio ..... 9.10-1 ....... {8.50-1 from Factory}
* Piston Type ............... Flat-Top
* Piston Depth ............. {-.041"}
* Head Gasket ............. .030"

360/170 HP ~ 4-Barrel
* Intake Manifold ......... #4095080
* Intake Valves ............ 1.88"
* Exhaust Valve ........... 1.60"
* Cylinder Head ............ 65.5 CC
* Compression Ratio ..... 9.00-1 .......... {8.40-1 from Factory}
* Piston Type ............... Dish {-.060"} = {6.8 CC}
* Piston Depth ............. {-.052"}
* Head Gasket ............. .030"
 
Engine Year Casting Intake/Exhaust CC
====== ======== ======= =========== ====
273 64-65 2465315 1.78" / 1.50" 57
273 66 2536178 1.78" / 1.50" 57
273/318 67 2658920 1.78" / 1.50" 57
273/318 68-74 2843675 1.78" / 1.50" 60
318 75-83 3769973 1.78" / 1.50" 63
318 77-86 4027163 1.78" / 1.50" 63
318 77-84 4027593 1.78" / 1.50" 63
318 FB 85-86 4323302 1.78" / 1.50" 62.6
318 Police 83-86 4323345 1.88" / 1.60" 75.1
340 68-71 2531894 2.02" / 1.60" 63
340 TA 70 3418915 2.02" / 1.60" 65
340 72 3418915 1.88" / 1.60" 65
340 73 3671587 1.88" / 1.60" 65
360 71-72 3418915 1.88" / 1.60" 65
360 73-74 3671587 1.88" / 1.60" 65
360 75-76 3769974 1.88" / 1.60" 65
360 76 3671587 1.88" / 1.60" 65
360 77-86 4027596 1.88" / 1.60" 65
360 77-86 4021051 1.88" / 1.60" 65
Just some more information, I hope this helps. I was always under the impression that the cop cars had 360 heads too. Here is a link to some more.
http://www.mopar1.us/sort.html
 
johnnymac2k6 said:
Well that poor kid in the thread the other day with the reman 318 was getting told left and right his 7.1 cr was great lol. Im with ya. Unless im hanging a few turbo's off the front nothing iron headed would be purpose built by me that didnt start with a 9 or 10.
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Depends on your cam. I'll take 7.6 over 9.5 if it's not gonna have anything in the cam department. If you're not gonna make a lot of power, no reason to not be able to run cheap gas. (in extreme cases you can even keep yourself from running pump gas in a mild motor) People who shy away from cams that're "too big" like the factory 340 cam have no business trying to maximize compression.
 
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