Making power out of the 318

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Dan the man said:
I have a question, is the magnum heads still limited to one intake manifold? They have said that the magnum heads are known to cracking, does this make them unusable?
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theres couple mopar intakes out for magnums, couple elderblock, airgaps popular, and few china airgap'ish intakes on ebay and amazon for 140iish bucks and free shipping with prime....of coarse getting LA bolt pattern drilled on magnum heads can be done by any competent machine shop for few bucks....
 
RustyRatRod said:
This is what I was talking about originally. You won't listen to seasoned, experienced people, yet, you said you would. You just "gotta have" 400 plus horsepower and I will "just bet" that at 15, you've never been in anything with an honest 400HP.

Now, before I go further, let me say, I'm not saying any of this in disrespect or trying to run you down, so lets get that outta the way now. I'm saying all of this as a fellow car guy that's been doing this since 1974, so I have a tad of experience. So don't get your panties in a wad and go off half cocked thinking I'm insulting you. I'm not.

Go ahead and get the 5.9 if you must, but I think as your first project it's a mistake especially since you already HAVE a 318. You're money ahead of the game RIGHT THERE. What will happen is, you will spend "whatever" part of your 3K budget on a whole nuther motor. Even the Magnum engines are getting old now and chances are slim you'll get one with low enough mileage that it won't take probably HALF your budget.

Then, even to reach 400HP with a magnum, you going to have to have "some kind" of cylinder head porting. You've already said your knowledge is limited, so that will cost another chunk of your 3K. 400HP will likely need 2.02 and 1.60 valves. Valves is another chunk. Gone. Valve guides sloppy? There's some gone. Heads will likely need milling to get them flat again. There's some gone. There's your budget pretty m uch down the toilet and we've not even gotten to intake, carburetor, ignition system, headers and on and on.

If you would just listen to common sense and experience, you'd get something running pretty quickly that would be respectable and keep your fire lit to collect parts as you go for build #2. As it is now, you're going to run out of budget. The project will stall and you'll lose interest and there it will sit. All these guys on here are spending money that isn't theirs with their recommendations. You need to think about that.
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I really like your thinking and I am not offended at all and I think it’s a really good idea but I’m still gonna think both ideas through. I’m not fully convinced yet on anything.
 
Magnum heads crack between the valves in the combustion chamber. For normal driving I wouldn't worry bout it but have no idea if it's a problem when your squeezing every last hp you can out of it
 
carmart1975 said:
There are many intakes now
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sort of. basically you have the eddy RPM air gap and the offshore knock offs of that and the M1 (which you don't want) and the M2, which you do want, but are impossible to find and a billion dollars.
 
dmopar74 said:
Magnum heads crack between the valves in the combustion chamber. For normal driving I wouldn't worry bout it but have no idea if it's a problem when your squeezing every last hp you can out of it
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Are there any iron closed chamber heads for a 360? Affordable aluminium heads? I don't mean to hijacked the op but I've been trying to find a good Affordable set of heads for a 360.
 
Dan the man said:
Are there any iron closed chamber heads for a 360? Affordable aluminium heads? I don't mean to hijacked the op but I've been trying to find a good Affordable set of heads for a 360.
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only factory cast iron heads with closed chambers are the 85 up 302 heads off 85 up 318s and magnum heads! there were the EQ magnum heads from the land down under every body loved but that changed hands and dont seem as populer last few years! lot of folks get the aluminum speedmaster heads on black friday sale for a real good price....if buying heads, buy best you can afford! heads what makes hp!
 
RustyRatRod said:
Go ahead and get the 5.9 if you must, but I think as your first project it's a mistake especially since you already HAVE a 318. You're money ahead of the game RIGHT THERE. What will happen is, you will spend "whatever" part of your 3K budget on a whole nuther motor. Even the Magnum engines are getting old now and chances are slim you'll get one with low enough mileage that it won't take probably HALF your budget.

Then, even to reach 400HP with a magnum, you going to have to have "some kind" of cylinder head porting. You've already said your knowledge is limited, so that will cost another chunk of your 3K. 400HP will likely need 2.02 and 1.60 valves. Valves is another chunk. Gone. Valve guides sloppy? There's some gone. Heads will likely need milling to get them flat again. There's some gone. There's your budget pretty m uch down the toilet and we've not even gotten to intake, carburetor, ignition system, headers and on and on.

If you would just listen to common sense and experience, you'd get something running pretty quickly that would be respectable and keep your fire lit to collect parts as you go for build #2. As it is now, you're going to run out of budget. The project will stall and you'll lose interest and there it will sit. All these guys on here are spending money that isn't theirs with their recommendations. You need to think about that.
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i'll play devil's advocate to this in the line of thinking of: how bad is the 318 he's starting with? i mean, just because he's got it doesn't mean that it's not rife with problems or needing machine work in much the same way a magnum would.

he's already established that there's a piston missing or messed up. so we know how far apart it is, so what else is missing and messed up? if the thing is gonna be worth a darn, hes gotta do pistons to bring up the compression ratio. so he's doing a bottom end. let's say he gets away easy from the machinist and all he needs is a next over, a clean up on the faces and for them to knock the cam bearings in and press fit the pistons.

he's mentioned that the heads he has basically need a full run thru, with parts likely, so there's another run thru the machinist's wringer. same as the magnum. or laying out cash for some useable heads... which is kind of a gamble, but not wild.

i guess what i'm saying is that there could be a lot of similarities betwixt the 318 and magnum in regards to machine work, which is something he can't do himself and a cost burden.

the benefit to the magnum, is that evidence has shown motors with reasonable mileage on them tend to fare better and can at times get away with just doing the bare minimum: rings, bearings, a dingle ball hone, and ship it.

it all hinges on the condition of the 318. if the bones is good, i'd go that route. cheap, easy, lots of parts, would come together quick without any additional supporting hardware. but if it's a tangled mess, the pendulum quickly swings back magnum.

but your point is well made. get it on the road as quickly and as cheaply as possible; then build a better motor on the slow boat. a fire kept stoked burns the hottest!
 
junkyardhero said:
i'll play devil's advocate to this in the line of thinking of: how bad is the 318 he's starting with? i mean, just because he's got it doesn't mean that it's not rife with problems or needing machine work in much the same way a magnum would.

he's already established that there's a piston missing or messed up. so we know how far apart it is, so what else is missing and messed up? if the thing is gonna be worth a darn, hes gotta do pistons to bring up the compression ratio. so he's doing a bottom end. let's say he gets away easy from the machinist and all he needs is a next over, a clean up on the faces and for them to knock the cam bearings in and press fit the pistons.

he's mentioned that the heads he has basically need a full run thru, with parts likely, so there's another run thru the machinist's wringer. same as the magnum. or laying out cash for some useable heads... which is kind of a gamble, but not wild.

i guess what i'm saying is that there could be a lot of similarities betwixt the 318 and magnum in regards to machine work, which is something he can't do himself and a cost burden.

the benefit to the magnum, is that evidence has shown motors with reasonable mileage on them tend to fare better and can at times get away with just doing the bare minimum: rings, bearings, a dingle ball hone, and ship it.

it all hinges on the condition of the 318. if the bones is good, i'd go that route. cheap, easy, lots of parts, would come together quick without any additional supporting hardware. but if it's a tangled mess, the pendulum quickly swings back magnum.

but your point is well made. get it on the road as quickly and as cheaply as possible; then build a better motor on the slow boat. a fire kept stoked burns the hottest!
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You're 100% right. The not knowing is the thing. But there's this. It costs him NOTHING NOT ONE RED CENT to tear down the 318 and inspect it. And I'll tell you, that beeotch would have to have .010" wear on the cylinders before I decided to bore it if I was on a budget.....well......I always am. LOL
 
RustyRatRod said:
You're 100% right. The not knowing is the thing. But there's this. It costs him NOTHING NOT ONE RED CENT to tear down the 318 and inspect it. And I'll tell you, that beeotch would have to have .010" wear on the cylinders before I decided to bore it if I was on a budget.....well......I always am. LOL
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3anki8.jpg
 
junkyardhero said:
it all hinges on
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The OP insist on two things he's unwilling to compromise so far 3.21 gears and 400 hp, everything else he's been open to. A 360 magnum will work better under these requirements.

Not that I don't think he couldn't build a 400 hp 318 but don't think it's gonna work to well with 3.21 gears.
Zero deck 318 a set of rebuilt magnum heads, airgap and a 235 ish cam should put him around 400 hp.
 
273 said:
The OP insist on two things he's unwilling to compromise so far 3.21 gears and 400 hp, everything else he's been open to. A 360 magnum will work better under these requirements.

Not that I don't think he couldn't build a 400 hp 318 but don't think it's gonna work to well with 3.21 gears.
Zero deck 318 a set of rebuilt magnum heads, airgap and a 235 ish cam should put him around 400 hp.
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I think that much cam with those gears would lack bottom end torque. ....but then he won't compromise on "I gotta have lope".
 
RustyRatRod said:
There's 3/4 or more of his budget GONE in the first paragraph. I mean seriously, yall need to pay attention here.
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Yeah tally that lot up and its $$$$.
i have made and learned from a few mistakes in the past, i started with expensive carbs a nice inlet headers and quickly leaned its pointless bolting that lot to a turd.... :)


I paid attention and looked at what he wants, and thought walk before you run.
He'll end up spending it twice over unless he gets a good start.
hence the bit about driving it while he saves do the rest

maybe i'm just a patronising old git


I did post before the revelation that he drives dads 500BHP big block :) lucky guy....!

he knows more about what he wants than initially indicated but you can't go wrong if you plan from the bottom end up, a good foundation is key.

Dave
 
RustyRatRod said:
I think that much cam with those gears would lack bottom end torque. ....but then he won't compromise on "I gotta have lope".
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that much cam with those gears is gonna be dog water for chure.

plop a single plane on there with a 750 DP for maximum suckage.

at least it'll sound cool...
 
junkyardhero said:
i'll play devil's advocate to this in the line of thinking of: how bad is the 318 he's starting with? i mean, just because he's got it doesn't mean that it's not rife with problems or needing machine work in much the same way a magnum would.

he's already established that there's a piston missing or messed up. so we know how far apart it is, so what else is missing and messed up? if the thing is gonna be worth a darn, hes gotta do pistons to bring up the compression ratio. so he's doing a bottom end. let's say he gets away easy from the machinist and all he needs is a next over, a clean up on the faces and for them to knock the cam bearings in and press fit the pistons.

he's mentioned that the heads he has basically need a full run thru, with parts likely, so there's another run thru the machinist's wringer. same as the magnum. or laying out cash for some useable heads... which is kind of a gamble, but not wild.

i guess what i'm saying is that there could be a lot of similarities betwixt the 318 and magnum in regards to machine work, which is something he can't do himself and a cost burden.

the benefit to the magnum, is that evidence has shown motors with reasonable mileage on them tend to fare better and can at times get away with just doing the bare minimum: rings, bearings, a dingle ball hone, and ship it.

it all hinges on the condition of the 318. if the bones is good, i'd go that route. cheap, easy, lots of parts, would come together quick without any additional supporting hardware. but if it's a tangled mess, the pendulum quickly swings back magnum.

but your point is well made. get it on the road as quickly and as cheaply as possible; then build a better motor on the slow boat. a fire kept stoked burns the hottest!
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the 318 i have is in very good condition just needs a good clean up like a hone, the rods are good and the crack has a Little surface rust i already have new rings and bearings for it i would just get the cam bearings done and i would need to by a oil pan and a front timing cover and the heads would need a full redo because they have like dried up sluge or carbon from the 360 they came off of and i would half to get new pistons because the owner before me droped one and cracked a peace off
 
273 said:
The OP insist on two things he's unwilling to compromise so far 3.21 gears and 400 hp, everything else he's been open to. A 360 magnum will work better under these requirements.

Not that I don't think he couldn't build a 400 hp 318 but don't think it's gonna work to well with 3.21 gears.
Zero deck 318 a set of rebuilt magnum heads, airgap and a 235 ish cam should put him around 400 hp.
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the 3.21 gears are not there to stay i will be putting a new 8 3/4 rear end when this one shreds then i will re gear then but i am not putting any money into the rear end i have now
 
carmart1975 said:
the 318 i have is in very good condition just needs a good clean up like a hone, the rods are good and the crack has a Little surface rust i already have new rings and bearings for it i would just get the cam bearings done and i would need to by a oil pan and a front timing cover and the heads would need a full redo because they have like dried up sluge or carbon from the 360 they came off of and i would half to get new pistons because the owner before me droped one and cracked a peace off
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What you're saying is: you're starting from scratch.
A set of stock replacement pistons is $250-300. Hoping for a re-hone to get the job done is wishful thinking IMO. The cost difference between "just a hone" and "bore and hone" is about the same as a set of pistons. The alternative is to get it "Just honed" then wonder why it rattles so loud (piston-wall clearance), or get it "Just honed" and find out it needs bored and honed again - either way is money wasted by trying to skip the bore step. Pistons plus a bore-hone is going to run you near a grand. Heads can easily cost that EACH, so there goes your whole budget and you don't even have a timing cover!?

You'd be money ahead to find a recently running motor - I posted a link to at least one, and there doesn't seem to be a shortage of them in southern CA. A magnum would be preferable mostly because an EFI motor isn't going to have as much bore wear as you'll see on a tired and abused LA motor. If you find a COMPLETE engine that was recently running, you'll have a lot less work to do. If it were me, I'd be looking for a whole freaking car that's got a busted axle or other minor issue that makes it cheap. Then you can sell off parts to recoup some costs and get a k-frame/engine/trans/driveline for pretty darn cheap, all things considered.
 
Mean416 said:
Nothing at all wrong with a 318. Or a 5.2 magnum. Or a 5.9 magnum. Or a 340.

They're all basically the same engine. Yeah there are differences but really they're easy to deal with.
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They look similar externally and that's about it. A more accurate description would be 273/318 are basically the same and 340/360 are basically the same and the late external balanced 340 morphed into the 360. The 340 HiPo evolved from the 273 Commando not the 318 . There's alot of 318 is the same as 340 internet BS its just an inaccurate claim.
 
Phreakish said:
What you're saying is: you're starting from scratch.
A set of stock replacement pistons is $250-300. Hoping for a re-hone to get the job done is wishful thinking IMO. The cost difference between "just a hone" and "bore and hone" is about the same as a set of pistons. The alternative is to get it "Just honed" then wonder why it rattles so loud (piston-wall clearance), or get it "Just honed" and find out it needs bored and honed again - either way is money wasted by trying to skip the bore step. Pistons plus a bore-hone is going to run you near a grand. Heads can easily cost that EACH, so there goes your whole budget and you don't even have a timing cover!?

You'd be money ahead to find a recently running motor - I posted a link to at least one, and there doesn't seem to be a shortage of them in southern CA. A magnum would be preferable mostly because an EFI motor isn't going to have as much bore wear as you'll see on a tired and abused LA motor. If you find a COMPLETE engine that was recently running, you'll have a lot less work to do. If it were me, I'd be looking for a whole freaking car that's got a busted axle or other minor issue that makes it cheap. Then you can sell off parts to recoup some costs and get a k-frame/engine/trans/driveline for pretty darn cheap, all things considered.
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very true and i like your thinking i wish i could buy a whole car but i just do have the room for 1 more so i would most likely buy just a motor that was already running or in a perfect world a motor and trans out of something
 
carmart1975 said:
the 318 i have is in very good condition just needs a good clean up like a hone, the rods are good and the crack has a Little surface rust i already have new rings and bearings for it i would just get the cam bearings done and i would need to by a oil pan and a front timing cover and the heads would need a full redo because they have like dried up sluge or carbon from the 360 they came off of and i would half to get new pistons because the owner before me droped one and cracked a peace off
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Other than displacement with the 5.9l which would help with lack of gear. It's mainly the heads cause there capable to reach 400 hp. Nothing stopping you using the 318 bottom end (but I would run less cam so less power but up to you) and could grab a set from a scrap yard and hope there just need a quick go over or buy a set of remanufacture ones or there's other head options. Which brings me back to the 1st step of your 318 build, Heads 2nd step figure out cam 3rd figure out cr for that cam etc..

If go 5.9l magnum then 1 and 3 are somewhat baked in.
 
Dartswinger70 said:
They look similar externally and that's about it. A more accurate description would be 273/318 are basically the same and 340/360 are basically the same and the late external balanced 340 morphed into the 360. The 340 HiPo evolved from the 273 Commando not the 318 . There's alot of 318 is the same as 340 internet BS its just an inaccurate claim.
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They're the same engine. Yes there are some key differences between them all that means they aren't 100% identical but again these are minor and easy to deal with.
 
carmart1975 said:
very true and i like your thinking i wish i could buy a whole car but i just do have the room for 1 more so i would most likely buy just a motor that was already running or in a perfect world a motor and trans out of something
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Mopars are spendy but Id say in my opinion and I dont know what things cost in your area but the A body 4 doors pop up with 318s in them from time to time for under 10 grand. Id take one and cruise it like a 74 Dart/Valiant 4 door with the v8 drivetrain. Then swap something in later like a 360 or a magnum. Not telling you what to do just tossing ideas. A Duster or something more popular is usually a rusted hulk going for top dollar and you have to tow it home...
 
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