150 HP LA 318 - vs - 230 HP Magnum 318

-
The 360 mag of the 90's is the 340 of the 70's.
I have both and the 360 just works with a little more cam.
 
64drtGt said:
find a semi low mileage maggie throw a few hundred dollars worth of parts on it and have a engine that will run circles around your LA with a carb and headers.
Click to expand...

ill take ya up on that offer too....I like the LA engines, and shaft rocker arms.
 
Still haven't pulled the trigger after all the work I did in your last post?

Stop stalling on the Magnum 5.9 swap, do iiiit. :blob:
 
I know, right! Pull the dang trigger and get it done! But I'm a skeptic... I always take forever to make a decision like this. I like the idea of the extra HP, but in reality I am quite satisfied with the 318, she's a goer! Plenty enough balls for me.

The 360 clearly has the horsepower advantage, but so far all I have been able to come across are the 318 Mag engines. And they seem to be somewhat of an improvement over the LA 318s.

So I will keep lookin... Keep watchin... The right donor will show up soon.

All I can say at this point is THANK YOU for all the insight and wisdom! YOU GUYS ROCK!
 
dude if your in nw Oregon im in Ridgefield I can easily find you a good motor pm me with your price range
 
bighammer said:
Do the heads on the 5.2 Mag have the same problem as the 5.9 Mag as far as cracking goes? Or are they the same heads?

Mark
Click to expand...

Same head.

MRGTX said:
The bench racing is ON.
:)

So how do you know to walk away from a Magnum with cracked heads? Are they always the kiss of death and require replacement?
Click to expand...

A minor crack in the head is not the kiss of death and not a required replacement. How do I know this? Because many people drive around with cracked heads and never know it for thousands and thousands of miles.

If you discover a cracked head in a rebuilding, replace the head.

You'll never know if the head is cracked unless you look for it.

mwls73duster360 said:
dude if your in nw Oregon im in Ridgefield I can easily find you a good motor pm me with your price range
Click to expand...
Now there's a good fella for you!
 
Your welcome, although the 5.9 isn't something that's to be skeptical about, it's sure fire. :D

I'd keep you 318 till it blows up, then replace it with a bigger motor if your satisfied. When your ready, check a truck junkyard in PDX or something when you get ready to rock. This way, you can take your time and collect your parts.

http://www.forabodiesonly.com/mopar/showthread.php?t=201632

Inspration!
 
The magnum 318 has tons of advantages as allready pointed out. I personally swaped a rebuilt la 318 out of my dailer driver/work truck/tow rig, with a 50,000 mile 318 magnum, put on a m1 dual plane intake, used the same TQ carb, same exhaust manifolds and all. It is deff stronger, and has never leaked a drop of oil. That was close to 10 years ago, and if you GAVE me a LA318, I wouldnt use it! I have a couple of customers with comercial trucks, one is a 98 ram 3500, with a mag360, it has a tick over 300,000 on it, and it might have cracked heads, but who know!
 
replicaracer43 said:
The magnum 318 has tons of advantages as allready pointed out. I personally swaped a rebuilt la 318 out of my dailer driver/work truck/tow rig, with a 50,000 mile 318 magnum, put on a m1 dual plane intake, used the same TQ carb, same exhaust manifolds and all. It is deff stronger, and has never leaked a drop of oil. That was close to 10 years ago, and if you GAVE me a LA318, I wouldnt use it! I have a couple of customers with comercial trucks, one is a 98 ram 3500, with a mag360, it has a tick over 300,000 on it, and it might have cracked heads, but who know!
Click to expand...

Not to rip on you, if your going to the trouble of a small block swap, 5.2 is second fiddle. You can church it up all you want, in the end, you have the same amount invested in a mild build, but less output.

Does not compute.
 
I put mine in my daily driver work truck, it was a really nice upgrade!! WTF is second fiddle about that?
 
I'm sure it is, the point I'm making is you can find the 5.2 and the 5.9 in the same price range. All things equal, you go farther with the 5.9, power, and price wise, that's all.
 
Yes, bang for the buck, horsepower wise, the 5.9 is the way to go. But this thread was about LA vs Magnum 318s.. and since I personally did this back to back swap, thats what my input is based on..
 
Nobody has really brought it up yet but a Magnum 318 will also get noticeably more gas mileage than the LA version thanks to the roller cam and heads even if the intake, carb, exhaust, etc. is the same. Also if you are building one up you can safely run 10.5:1 compression (static) in a Magnum which is what you get with a set of zero-deck flat tops. My Magnum-headed 360 with KB-107s runs fine on pump 91 and the timing is close to optimal. An open-chamber LA engine can barely handle 9.5:1 on pump gas without pinging or making too much heat. Overall Magnums are more efficient so you can make more power AND get better mileage if you like to drive your A-body a lot.

The only good reason IMO not to choose a Magnum over an LA is due to the cracking heads issue which is the case with most used Magnums... and even then I'd just get a pair of EQ replacement heads at $300 each, problem solved!
 
Overall Magnums are more efficient so you can make more power AND get better mileage if you like to drive your A-body a lot.
Click to expand...

Agree.The magnum is more efficient as it should be with more modern components. Magnums get a bad rep.with fuel mileage because they were originally in heavy trucks/vans behind a lousy 4spd. automatic for the most part. Local club member swapped 318 magnum & 5spd. from Dakota along with PCM (modified for his application) into his 72 dart and pulls down 23/24mpg on HWY with 3.23 rear.

Oldschoolcuda
 
bighammer said:
Do those numbers sound right?

I looked on Wikepedia, it says the LA 318 is 150 horse power. The Magnum 318 is stated to have 230 horse power.

Since I am in the market for an engine swap, I am considering the Magnum 318, since I have not yet located a 360. (And I have found a couple 318's)

Seems like a decent upgrade, although not as much horsepower as the 360 swap, I would think it would be a noticeable improvement over my tired LA 318.

BTW, the Magnum 360 is rated at 250 horsepower.

What thinks you?

Mark
Click to expand...
Not correct. The LA 318 was rated at 230 horsepower
 
bighammer said:
Do those numbers sound right?
Click to expand...
Well that depends.
I see this is an old thread, but I'm gonna unload anyway.
The 150hp 318s were rated 8/1, Emission slugs with retarded timing, crappy heads, tiny 2bbl Carter carbs, and a restrictive single exhaust system. Being 1973; that 150hp was a net rating.
The 1972 engine, just one year earlier, was rated 230 hp, gross. It was rated at 9.2 Scr and, closed-chamber crappy heads, way better timing, a single-plain intake and a bigger Rochester carb.

The point is that if you are rebuilding the 318LA anyway, with new pistons, then the Magnum advantage quickly loses it's shine. If you already have a Magnum, and an intake for it, then it makes sense to use it; just don't use the factory cam.
But don't throw an LA away if it's what you already have.
______________________________________
But if you have neither, you know what I'm gonna suggest right ....................... it costs the same for machining any SBM regardless of size, and the KB107s for a 360, drop in at about .012 below deck, so with .028 gaskets you already have a flying headstart on anything else SBM; no matter which direction you take it.
From there, everything else SBM can be installed, including the smog-era crappy 318 heads..... altho, that would be throwing away the Tight-Q advantage.
And besides all that, the 360 falls together with a nice modern high compression ratio real easy, so you can run a pretty good sized cam, and not need a stinking hi-stall, nor race gears in the back, altho for street duty, the big cam and 2.73s are not the hot ticket.

Just try to make 185/195psi with a 318 and you'll see what I mean, whereas with a 360, it's harder to not exceed those numbers than to sneak up on it. And I guarantee you that, that when running such hi-pressure, on the street, you will not care one bit about the size of the cam.....

Meh, some people will aver that you don't need big pressure on the street. Ok fair enough, it's true you don't. But if you end up at 140psi or less, two things are gonna happen;
1) If you come from running say even 185, you are gonna be one sad SBM owner; and
2) now you gotta throw another wagon-load of cash at it, to try and find the smile that the hi-pressure engine used to light up your life with. But no matter what you throw at that low-pressure wanna-be SBM, that smile is just not forthcoming. You will buy a hi stall, and big rear gears, perhaps multiple times, and see your fuel-mileage plummet into the single-digits, while the hiway cruise rpm will drive you nuts, and on and on it goes.
Look,
building a high-pressure 360 will cover all the bases and, relatively speaking, is at least as cheap, or cheaper in the long run, as band-aiding any smaller engine, with a suitable convertor and gears, which will still never compare to a hi-pressure 360 anyway.
Well unless you supercharge your smaller engine....... but there goes the budget.

Dear Mopar HotRodder, do yourself a favor; if considering a low-compression/ small displacement style engine, you might as well budget an overdrive right from the get-go. So now, you can run a proper stall and gears to get the rpm up to where it needs to be, to have fun with, while simultaneously being able to drive it anywhere anytime. Then gear the daymn thing to run outta power at around 55/60 mph in Second gear, but build it to rev a good 10% higher, than it needs to, just so you can hear your stinking Mopar wind up!, and put some decent closed-chamber heads on it.

For instance to hit say 60mph at 5500 rpm with 27"tires, your car will need an overall roadgear of 6.63.
If yur running an A500, it has a Second gear of 1.54 so then, 6.63/1.54= 4.30s in the back. and with those,
65= 2400 in overdrive and Locked Up, badaboom!
Knowing this now, you can select an appropriate cam.
Having done that, you can now select the heads.
Having done that, you can now work out the Scr to maximize the pressure, so you can run as low, yes as low, a stall as will make you happy.
Now, I gotta tell you, when coming up behind a slowpoke doing 55 in a 65, downshifting from locked-up in overdrive, to into Third gear, your engine will hit just 3200 in direct at WOT, or 5000 in Second, so pretty much your best choice is Third gear. The thing is, at 3200, a NA lo-compression 318 with a modest cam pulls like pushing a limpdyk; you will only ever try that once in traffic.
Yur gonna want that hi-pressure 360, cuz when you nail it in Third gear, you will already be at 5000 rpm=85mph as you fly by the driver, and see his stunned expression. I know this is true because mine does that with 3.55s lol, all be it in Second gear, with a 4-speed, and at 7200/lol.
Now;
meh, some will say you don't need a 360 to have fun with, on the street, and that's true. But I say, if yur gonna spend the coin, yur gonna get way more smiles per dollar out of the hi-pressure 360. And you can tell all your friends, who are gonna insist that the 340 is the king of smallblocks, to kissyurazz. Just ask any hi-pressure 360 owner if they ever regretted not having built a 318. Don't ask a 318 owner, their egos get in the way.

Doing it any other way IMO, is just looking for disappointment and/or a never-ending parade into and out of the shop, do-overs, or finally, getting a hi-pressure 360.
BTW
Yes I have, built 318s and owned several HO340s ; which is why I don't have one anymore, lol.
Meh!, it's only 42 cubes guys will say. Well, when yur sitting on the line, with your convertor pulling at stall rpm and my 360 has 13% more torque than yours right at the line, tell me how much you don't mind having 22 fewer cubes .......
Or; when you are screaming your 318 down the hiway at 3600rpm with 4.30s, and pulling 9mpgs, to my 367 idling at 65= 1600rpm in double-overdrive and pulling 30 mpgs; go ahead and remind me it's only 42 cubes.
Or; when my 367 pulls 93 mph in the Eighth, in Second-over, doing under 6200rpm, to your 318 hitting 93 in the quarter @5500...... remind me about the 42 cubes.
Or; remind me why guys install 4"cranks in 365s; It wouldn't have anything to do with the 40-odd cubes now would it?
Meh, lunkheads I say.

Happy HotRodding

PS;
can a 318 even pull itself at 65= 1600 rpm? IDK.
and if it can, how much throttle will it take? and
how do you give it the timing it craves?
I know with 2.20 rear gears 65=a tic under 1800, so that seems to be possible ..... but 1600 is still 11% slower ......
 
Last edited:
A low cr 2bb 318 with headers in dyno trim made 189 hp so to me that gross 230 hp number is way over rated.
 
Lets not forget the extra 20 horsepower that the 318 in 73 in the roadrunners with dual exhaust had. They were rated at 170 horsepower while the single exhaust was rated at 150.
Same motor but dual exhaust, 20 more hp.
 
Jadaharabi said:
That's not forget the extra 20 horsepower that the 318 in 73 in the roadrunners with dual exhaust had. They were rated at 170 horsepower while the single exhaust was rated at 150.
Same motor but dual exhaust.
Click to expand...
Or the 165 net HP LA318's in mid 80's to 91
 
I don't think the 318 heads are necessarily bad, it seems they flow better than a lot of Fords 302 heads but 5.9l/360 heads are just gonna give you a big jump in power, other than throwing a cam 4bbl exhaust on a running 318, I don't know why people insist on running 318 heads when looking for power. I bet if all LA 318s came factory with 360 heads since the early 70's people would have a way different view on 318 performance potential.
 
91 5.2 is a Magnum and was rated 235 HP with the "large exit" Magnum manifolds.

Rating went down to 230 with smaller outlet manifolds.

5.9 was rated 245 HP and was the same build as the first gen "crate" 360, rated at 300 gross HP.
 
You must log in or register to reply here.
-

Back
Top