POLL: 360 magnum or 3.58 stroke 340?

What engine would you build?

  • 360 Magnum

    Votes: 58 49.2%

  • 3.58 Stroked 340

    Votes: 60 50.8%
  • Total voters
    118
  • Poll closed .
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gliderider06

gliderider06

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Wondering what everyones thoughts are? I have a stock bored 340 that I was planning on 3.58 stroking, since I already havea 360 crank/rods etc...
Now the quandry comes in to where I just got a complete 99, 5.9l magnum for really dirt cheap from a buddy of mine, with 100,000 ish miles on it. I can get a new cam for magnum, ring/bearing it etc... and probabally make same or more HP than the 340. I already have a LA 360 in the 69 Dart now, that runs great. I just wanted to do another motor for the car and make a little more power.
What engine would you build?
 
For me it would be simple:
360 magnums are everywhere.
340's are not.
I love 340's but there's just not many around anymore. I would build up that 360 magnum and then build up that 340 slowly over time. And when the time comes, you can swap it in or sell it for good cash.

**Edit** Now keep in mind with a 360 mag, you will need to either get a long snout cam for mech. fuel pump or get an electrical fuel pump setup.

Not sure if you knew or not.
 
In my book, it comes down to heads. If the heads you have for the LA are better than the mag, build that, assuming you don't want to dump a bunch of money into them anyhow, or buy others

Personally I doubt the bore size by itself, all other things being equal, is going to make 'that much'
 
Sell the 340, build a 360. Unless you're stuck in the '70s and feel that there's something magical about a 340 that a 360 can never achieve...
 
Posts 2 thru 7,,,,,, x2
Its easy to make good power out of either the 360LA or the 5.9Magnum. But if your LA is already putting out hard, it will be expensive to better that with the 5.9 or any SBM for that matter.
Have you given any thought to other alternatives?Or to your goals?
For instance, at 100,000 miles that Mag is just nicely broken in.Perhaps a head refresh and its good to go. Then you could swap it into your Dart, and do a number on that LA.
Or go BB. Or turbo something.
Monster low-end torque is incredibly addictive.It becomes an exercise in self-control. Top end SBMs arent the most streetable DDs. But a 450hp/500#ft turboed earthshaker?, that sounds like a tonoffun.
You could stick that 3.58 in a teener,put some pressure to it, and fry some tires.
Oh wait.Thats what I would consider.Or maybe a bit more stroke. Yeah a 4 incher sounds about right.I bet I could put a pretty fair cam in that baby. All that stroke makes a lotta room for a lotta air.Maybe I could make 550#s.I guess I might have to back-half the old girl and make room for some real tires.I guess Id have to give up the stick though. I guess I could get used to an automatic.Lets see, how deep are my pockets? Oh dear, Im semi-retired, and scrounging around for grocery money. Maybe in the next life........
 
Personal preference. I have a buddy that races a 3.58 stroke 340 w W5 heads in a Plymouth Arrow that is in the 5s 1/8 mile. Im sure a 360 Magnum could do the same thing. I have heard that 340 bottom ends are stronger than magnum blocks, never measured to say that is fact. If you are building from scratch a 360 will be cheaper, as everyone has already stated. I build 340's because I have a boat load of them. Most of them go into real 340 cars that people want the date correct block for. No numbers, who cares.... 360 will make just as much power. I was back and forth a few yrs back and I ended up going 4" stroke in a .030 over 340. 340 block was already prepped on the stand and I had a dozen more tucked away.
 
This is kinda what I have been thinking. The Magnum is/was running when he pulled it from his rusted out 15 pac van. I can pull it apart and get a new cam for it, freshen up the bottom end etc, a lot cheaper than it will cost me to completely rebuild the 340 the way I want to do it. I hear that folks are getting in the 11's with magnums, with a mild build.
 
Magnum. A 3.58 stroke 340 is the same thing, but an LA. With the Magnum you have a roller cam on the cheap. A no brainer, really.
 
To put a 360 crank in a 340 block, the main journals on the crank are going to have to be turned down. Originally, I preferred the 340 with the 360 crank. After giving it some thought, if the 360 block will take a .040 overbore, do that and sell the 340. As far as I know the only 340 blocks that have stronger main webs are the T/A / AAR blocks. They were made that way to accommodate 4-bolt main caps.
 
2 Darts said:
To put a 360 crank in a 340 block, the main journals on the crank are going to have to be turned down. Originally, I preferred the 340 with the 360 crank. After giving it some thought, if the 360 block will take a .040 overbore, do that and sell the 340. As far as I know the only 340 blocks that have stronger main webs are the T/A / AAR blocks. They were made that way to accommodate 4-bolt main caps.
Click to expand...

you can buy a 3.58 stroke crank with 340 mains from scat...or MP...
 
If it were I, I would do a .030 overbored 340 with the 3.58 crank stroke of the 360 for a total of 372 cubes.
But I opted for a 4.25 stroke crank instead.
(442 cubes)
 
The 340 is really nostalgic and I can understand being drawn to it, but a roller cam and a modern combustion chamber. It would be the 360 for me.

Ted
 
Being he all ready has it, (340) now is the time to use it.
Selling it & rolling the money over into the 5.9 is fine.
 
Sell the 340 to someone doing a restoration.
Build the 360 and live happily ever after........
 
Roller cam block hands down.

If I had it all over to do do again I'd go Magnum or Gen 4 Hemi.
 
oops,just re read '69 Dart.
for resale a 340 Dart is usually best.
now...how fast do you want to go?
 
I also have both a built 340 and 360 mag.
I would tear down the mag and see what condition it is in.
The mag I rebuilt had awesome looking cylinder bores, but the crank was scratched up, which required turning.
Also check the heads for cracks, both heads on mine were bad.
 
A 360 is a stroked 340. Why ruin a 340, if you want to stroke it just use the 360. Do you really think you tell the difference with + .040 diameter bore? Plus, if you use the 360 you get the stronger, larger, main bearings.
 
-Just a original type guy, I'm stuck on the ole 340, build it, run it, save the 360 Mag for if and when the 340 might give up (IF at all) just my 2 cents..... Love the old engines, as there are A LOT of 360's around, just to have the 340 to "save" it for yourself...Build the 340 over time, and do the 360 now, if you plan to sell one or the other, build the 360 and sell it, to build the 340.....
 
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