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Discussion Starter #1
I would like to use the Edelbrock 2176 Performer intake on a '94 Magnum 318 engine. I know they make an intake to fit this engine directly, but it's an air-gap design and for what I'm doing I don't want an air-gap design. I need the exhaust crossover passage under the plenum.

So back to the 2176, I know the bolt holes don't line up. What about the intake ports? Are they the same and line up okay? I can deal with the bolt hole issue.

I'm assuming also that the heads on a '94 Magnum engine have the exhaust crossover passage in them. Can someone confirm whether they do or don't?
 

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Magnum heads do not have the exhaust crossover.


There is no need for the exhaust crossover on a stock magnum motor.
Other than the bolt holes, the intake ports will line up, but I think the thermostat will interfere with the A/C compressor if you have one as the thermostat and bypass are in a different location.
 

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Discussion Starter #3
I do have A/C, although I can fabricate any brackets I need and I might be able to shift it a little bit to clear the thermostat and bypass.

I do need that exhaust crossover though. Rats. I'll have to come up with another idea. Nothing is ever easy. Just brainstorming here - do earlier heads fit on this block?

With the 300,000+ miles on this engine, a whole engine swap of some sort comes to mind.
 

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Discussion Starter #5
I want the exhaust crossover because this is a year-round daily driver. The only intake I can find that directly fits this engine is the Edelbrock 7577 which is an air-gap design, and I think an air-gap design would be too cold and allow fuel puddling on the plenum floor. I may end up trying it anyway because it's the only one I can find and go from there.
 

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It won't fit. Just as soon as you set it onto the Magnum block you'll see why. It's weird. Early on, people were using LA intakes on their LA blocks with Magnum heads. That works, as long as you address the attachment (bolt) issues. A full-on Magnum block, with Magnum heads will swallow the LA intake. The intake sides don't even touch the heads. Weird, I know, but that's the deal. Just set it up and you'll see. I was looking at doing EXACTLY the same thing some 16 years ago with my then new 360 Magnum, and 2176 Eddy. Fuel puddling isn't gonna be an issue. Get a modern carb with electric choke. Aluminum absorbs/dissipates heat at a much higher rate than cast iron, and you still have your coolant/thermostat tie-in, plus convective heat from the engine once it's run some. Your other option would be to look around for an M1 from Mopar Performance that is a carb unit for Magnum. You still won't have the heat cross-overs, but it's a non-AirGap design. P5249500 They don't make 'em any more, so good luck, but the Edelbrock AirGap design is so good, you're not gonna miss it. Remember, on the LA's, the AIr Gap doesn't use the heat crossovers (with a carb) either, and it's generally regarded as the best street intake for that engine in the 400HP street-friendly setup. BUT, that properly working choke is vital.
 

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Discussion Starter #7
Thanks Gen1dak. That's very helpful. i don't think I'll give myself the opportunity to set it up and see. I'll take your word on the block issue and save my money for the 7577. This project is down the road far enough that I'll keep my eyeballs open and maybe I'll turn up that M1 Mopar Performance intake. I have actually never used an aftermarket aluminum intake manifold on anything to know maybe they don't have the fuel puddling issue. I know I've seen it on factory cast iron intakes where I blocked off the crossover passage. Thanks again.
 

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Discussion Starter #9
Thanks for those links. Looking at the Magnum heads with the LA intake bolt pattern, it's not clear but it looks like these heads are designed to be used on an LA block. If I understand Gendak's comments correctly, the Magnum block has a taller deck height so even with these heads an LA intake still would not fit. Are the Magnum heads a lot better than the LA heads or something? I'm missing the point of wanting to put Magnum heads on an LA block.

I really wanted this to be a bottom dollar project. (I have other reasons I simply want to go to a carburetor.) Start swapping heads and I know (from experience) that it's pretty easy to just do one more thing and one more thing. If I start getting that involved I would just as soon find an old 440 and drop in it.

On that note, I wish to cripe I had kept the engine that was in a '77 New Yorker that belonged to my dad years ago. That car had a 440 High Performance engine, so stated on a sticker under the hood. That engine was unreal, especially given the year. Long story short, that car came to a demise and was replaced by a '77 Newport with a 400. That car was a freaking dog, definitely reflective of the year. There was WAY more difference between those motors than 40 cubic inches. To this day I wonder what the differences were, and I would love to have that 440, but it's long gone.
 

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As far as stock heads, the magnum head is far superior to any LA head - depending on your usage.
That being said, very few magnum heads will not be cracked between the valves and then often into the valve seats - and are not worth playing with except of the very low low dollar setup. Aftermarket magnum heads are superior in a few areas.


Why carb??



As far as the 77 440, I don't know of any such think as a HP 440 that late, unless it had some sort of police package on it. Or not the original engine.
What color was the motor painted?
 

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Discussion Starter #11
Why a carb? I have an experiment going.

I'm sure the '77 New Yorker had an original engine. What color was it? Oh boy, that's been a long time ago. For some reason I'm picturing dark turquoise valve covers, but I'm not sure about that. That could be some other car. I really don't know. I can picture that sticker though and I know how that car drove. The thing was mean.
 

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Basically, the Magnum head was the culmination of everything Mopar enthusiasts had been doing to the LA head for nearly 30 years. Basically closed chamber mid-80's 318 heads, with 360 size ports. They lowered the exhaust port floors, straightened out the "dog legs" and reduced the size of the valve stems. At 6,000rpm, the stock Magnum head and the old 340 X head were within 5hp, according to Chrysler's own engineers. However, the Magnum does this with a 1.92" intake valve compared to the 340's 2.02" intake valve. Due to the heart-shaped closed chambers, you have better flame propagation and greater quench, which resists detonation and cleans up emissions a bit. Basically, either head will ding 400hp around 6,000 rpm. The Magnum is a bit more efficient at it. And since it's a lot like the old 360LA, it does have cracking issues in stock form. However, on the street, in anything short of some max-effort setups, a good 360LA top end is fine, especially since it matches the the LA block. The replacement parts are made to be used as LA's or Magnums. Magnum replacement heads sold to fit LA blocks do, unfortunately, require the Magnum rocker assemblies as well.
 

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True Gendak, only thing is 340X heads were never very common.


The magnum rocker assemblies aren't bad and are available in several ratios, even stock it is 1.6 vs. the 1.5 in the LA so you gain a bit of lift.


The last couple of years of the 318 LA heads weren't bad either, I would want hardened seats if it is going into anything that will be driven a good many miles.
 

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dropped in hp each year until 1978, when it was rated at 255 hp (190 kW) (in police specification) and limited to Chrysler New Yorkers, Chrysler Newports, Dodge Monaco Police Pursuits, and Plymouth Fury Police Pursuits.


So not really very HP, but they were all pigs by that point and it would have ran much better than the 400, esp. if the 400 was the standard 2 BBL version.
 

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I do have A/C, although I can fabricate any brackets I need and I might be able to shift it a little bit to clear the thermostat and bypass.

I do need that exhaust crossover though. Rats. I'll have to come up with another idea. Nothing is ever easy. Just brainstorming here - do earlier heads fit on this block?

With the 300,000+ miles on this engine, a whole engine swap of some sort comes to mind.



Why not just put a used 5.9 magnum in? Or an old LA 360?

Hard to beat fuel injection though, not sure what your experiment is.


If going carb, you also have to address the spark and timing too.
 

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True Gendak, only thing is 340X heads were never very common.


The magnum rocker assemblies aren't bad and are available in several ratios, even stock it is 1.6 vs. the 1.5 in the LA so you gain a bit of lift.


The last couple of years of the 318 LA heads weren't bad either, I would want hardened seats if it is going into anything that will be driven a good many miles.

Yeah, just showing the advances incorporated thru the years over the best of the LA's.

You point out an interesting fact on ratios. It does open up more options. I was just talking from the point of cost, already having the LA rockers.

Yeah, the 302's were the ones Mopar intro'd on their cars in the mid-80's. Don't know why it took them so long to get them into the trucks. They took that head, added standard 360-size valves, ported it out and power jumped 40%, and they were sold thru the Mopar Performance catalog. The late 90's 360 "308's" were almost as good, but were not true closed chamber heads, but I'd love to have some as bolt-ons. They'd get edged out by properly ported 302's, but the cost difference of hogging out and re-valving the 318 heads wouldn't justify the modest difference in peak power. I did manage to snag a set of the 302's last year. Ran out of the u-pull it yard like the Grinch stealing Christmas. Looking forward to putting them on something after a little cleanup, maybe a 3-angle job. Awesome for torque and midrange.
 

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A good read on a 390+hp 360 build:
https://www.hotrod.com/articles/mopp-0003-360-engine-build-top-end-part-4/
A 400hp 318 Magnum-head swap build: https://www.hotrod.com/articles/mopp-0409-318-engine-build/
A 400hp 318 LA buildup: https://www.hotrod.com/articles/318-small-block-build/
Adding 100hp with a few simple bolt-ons to the 318: https://www.hotrod.com/articles/mopp-0312-318-long-block-bolt-ons/
Also add 129hp to a 5.9 Magnum: https://www.hotrod.com/articles/hrdp-0804-small-block-mopar-engine/


Whether 318 or 360, with similar parts, both top out around 400hp at 6K rpm. That points to the heads as the limiting factor. Some serious work will increase the power modestly, but for a lot more, ya gotta move up to W2 or W5's. On the street, there's no denying the extra 42 cubes in the 360, and that instantly equates to an easy 30lbs more torque in even very mild setups. Much more when souped up a bit. If you look at the dyno charts, the 318 pretty much pulls even with the 360 around 4K rpms with similar setup. That's where the heads become the major factor, all else being equal beyond displacement. It's all in what you wanna do, how much you wanna spend, and what you already have.
 
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