340 Vs 360

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dusterdoug said:
Combine the two...

Get a 340 block that will go .030 to 4.07, or even .040 to 4.08

Find a 360 crank CORE, (probably free if you look) and since it will have to be turned anyway...turn the mains down to fit the 340 block.

Shelf (hyper = cheap) pistons are available and with a light SCAT rod, you'd have 372+ tire shredding cubic inches inches! HUGE bang for the buck, it you ask me.

Seems like I see a few reasonably priced 340 cores her in CA every week...
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QUOTE{all you would have is a .070 to .080 overbored 360 with .300 cut

from the mains of a cast crank. "huge bang for the buck" hardly.......more like a huge cut from your wallet}.

REALLY !!!!!!
I had a 340 with a 360 crank in it and the 340 came out of a boat on top of that... that was a very fun engine .. it is built right and mine was .. in had it pro built .Not as bad as you would think on the price to have it built that way. the price was some wear around 4.500 and that was 15 years ago ..
Best time was 12.03 @ 110.68 with a 60ft of 1.62. now super fast but fun . I put a ton of cars on the road home back home .. if I would have a better rear set up it would have gone in the 11:90 or 80s.

[ame="http://i58.photobucket.com/albums/g254/rules371/Video12.mp4"]
th_Video12.jpg
[/ame]
 
318willrun said:
But what if the people with the same cubic inches (all being equal) live at 6000 ft. above sea level? Then wouldn't the longer stroke of the two have more validation? Wouldn't a 318 stroked to a 349 have more torque than a 340 bored .060 over, all else being equal.... Ahhhhh, the X factory, altitude.......... lol
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If they both live at 6000ft above sea level then they will both be affected by atmospheric conditions equally.

stroked 318 vs overbored 340 is a good topic for a new thread. :D
 
kwazy these pesky wabbits...there is no end to this argument...they are all winners...some like blonds,some like brunettes,some like redheads,I like em all...each has its quirks but they all can perform depends on how much you put in..to get the desired results and most of all how much money ya got...if its MOPAR you are a winner...
 
318willrun said:
But smaller displacement needs a less cfm carb meaning the smaller displacement is doing as much with less, so if the carbs are equal the larger displacement has less to work with so if equal the smaller has more and the larger has less so its achieving more by using less.... heh??
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Smaller engine needs less carb, cam, head flow to make power at the same peak rpm as the larger engine, but the output would be lower for the smaller engine thats why most poeple say there's no replacement for displacement

But Horsepower don't care if you make it through torque or rpm, to make the same HP no matter the displacement
will take similar carb, cam, head flow.
 
318willrun said:
Sure, it makes sense! See, they are say'n all being equal (same carb, cam, etc), the bigger displacement makes more torque. But if the smaller displacement has the same carb, then it has more because the cubic inches per cfm isn't the same. But if you give the cfm's according to displacement, then all isn't equal because the bigger engine has a bigger carb meaning more opportunity.... Seeeeeeeeee?????????????????
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I see what your saying cfm per cubic inch is different if built with the same top end the 360 will make more torque but 340 will turn more rpm thats why they equal out. Because what I like to call dynamic cubic inch a 340/360 are there static engine sizes (non running) but a running 360 turning 6500 rpm would have a dynamic CID of 360 x 6500/2 = 1, 170, 000 cubic inches per minute and a 340 would have to turn 6882 rpm to equal out
(1, 170,000 x 2 / 340 = 6882) and a 318 would have turn 7350 rpm. Rpm is basically another way to add displacement to you engine.
 
frosty_the_punk said:
If they both live at 6000ft above sea level then they will both be affected by atmospheric conditions equally.

stroked 318 vs overbored 340 is a good topic for a new thread. :D[/QUO

Hey let's here what everybody got to say !!
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SBDart said:
frosty_the_punk said:
If they both live at 6000ft above sea level then they will both be affected by atmospheric conditions equally.

stroked 318 vs overbored 340 is a good topic for a new thread. :D[/QUO

Hey let's here what everybody got to say !!
Click to expand...
If they both were exactly 349 cubic inches, no matter how they arrived at those cubic inches, it would be 100% an equal tie if cam, heads, intake and carb were all equal, JUST ASK FROSTY:tongue5:
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Something I must say. Many threads (not just this one) loose their intention to stupidity. And then people start saying how pointless, stupid, and all how much of a waste the whole thing is. Nobody is MAKING you look, read or reply. You are not strapped to a chair with someone forcing your finger to push the button to view or reply. I see many uninteresting threads, and, I just don't bother viewing or replying. Don't bother making your short life miserable by forcing yourself to read nonsense you don't agree with. For me, I've had many of good laughs, especially with Frosty. I'm sure there is much we agree upon and I'm sure he is a great guy.
 
Agreed man, I thoroughly enjoy "bench racing" and the banter that goes with it.

I really don't think anyone is terribly upset by people going a little off topic at times, that's the nature of how conversations work. one minute you're talking about the weather and then you're talking about politics then food then movies etc.


I think as long as nobody gets nasty or starts talking down on others there's no reason for people to get upset or complain about the contents of a thread.
 
318willrun said:
If they both were exactly 349 cubic inches, no matter how they arrived at those cubic inches, it would be 100% an equal tie if cam, heads, intake and carb were all equal, JUST ASK FROSTY:tongue5:
Click to expand...

I definitely didn't say that.
 
SBDart said:
frosty_the_punk said:
If they both live at 6000ft above sea level then they will both be affected by atmospheric conditions equally.

stroked 318 vs overbored 340 is a good topic for a new thread. :D[/QUO

Hey let's here what everybody got to say !!
Click to expand...

I'm not stopping anyone from having their say, but I think that when it comes to changing bore/stroke ratio you also end up changing rod/stroke ratio, bearing diameters. rod length/weight, skirt length, piston weight, valve shroud etc etc it gets very involved and it would easily warrant it's own thread.

This thread was originally about comparing a smaller motor to a bigger motor and that is a LOT more cut and dry, If you have two identical motors and you stroke one of them to increase it's displacement it will make more torque. Period.
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318willrun said:
Something I must say. Many threads (not just this one) loose their intention to stupidity. And then people start saying how pointless, stupid, and all how much of a waste the whole thing is. Nobody is MAKING you look, read or reply. You are not strapped to a chair with someone forcing your finger to push the button to view or reply. I see many uninteresting threads, and, I just don't bother viewing or replying. Don't bother making your short life miserable by forcing yourself to read nonsense you don't agree with. For me, I've had many of good laughs, especially with Frosty. I'm sure there is much we agree upon and I'm sure he is a great guy.
Click to expand...

Just having a good laugh. These kinds of threads get ridiculous. :happy1:
 
7 days and 3000 + views
The thread people must love to hate :)
 
273 said:
7 days and 3000 + views
The thread people must love to hate :)
Click to expand...

the only person missing is Betty Crocker, with her engine recipe book. lol
nothing new in these threads, same tricks, same parts.
 
had both...69 x head 340 10.5 compression (never bored) and now a 360/380 magnum crate and as drivebility in the city , gas price , 9.0 compression and tons of torque , no leaking valve cover gaskets ...can stand traffic all day long ... in 11 years in the mopar thing , my favorite is the 5.9 magnum , even drove it stock in a Durango r/t , in street maners it is amazing . Strong , reliable , cheap and its just the evolution of the others and Mamopar took the best of everything except high compression... oh and btw look up how the cam specs of a 5.9 magnum is ,you ll see that its B******* but still kicks the 340 x/j headed high comp"s *** ALL DAY LONG...

my 2 cents .
 
I thought this thread might be fun to drag back from the dead. Since I am a Molnar Technologies dealer I will add these thoughts.

Currently Molnar list 6 different variations for a 340 main journal with 3 different rod sizes available.

While they only offer 2 different strokes for a 360 main journal. 3.79" / 2.100" rod journal and 4.00" with 2.125" rod journal.

So your asking why does this matter?

Well if you're going to build a race stroker 360 with a 4.00" stroke crankshaft you are limited to using 6.123" long rods because of the 2.125" rod journals.

If you're using a 340 block you can buy a 4.00" stroke crank with 2.100" Chevy journals that accept off the shelf rods available in lengths up to 6.300" long.

Because a SBM has a really tall 9.60" deck height when using a 6.123" long rod in a 360 with a 4.00" stroke crank you end up with a 1.477" compression height

and a rod stroke ratio of 1.53

If you use a 340 block with a 4.00 stroke and a 6.300" long rod you can end up with a piston that has a 1.30" compression height and a rod stroke ratio of 1.575

The 340 has a 2.50" diameter main journal and the 360 has a 2.81" diameter journal. Fun fact: All NHRA Pro Stockers also use a 2.50" diameter main journal.

Just some food for thought when you are deciding if your next project is a semi race engine or a real race engine trying to gain every horsepower available.

Tom
 
273 said:
340 vs 360 on a full out race engine build both taking out to there max rpms the 340 would have a advantage over 360 with its bigger bore (better breathing) and shorter stoke (higher rpm capability).

340 powerband will be 300-500 rpms higher than a similar 360 which would make the 340 needed more stall and gear to give same performance as a 360. And yes a similar prepared 360 will make more torque then a 340 but that only matters if your racing dyno numbers with the right gearing both will put similar torque numbers to the ground. The main advantages a 360 has lower cost power will be lower in the powerband and requiring less gear and stall, all around just a little more streetable. Or use 340 block with a 3.58 crank and have best of both worlds.
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Ten years later I'm still making the same arguments lol :)
 
This thread is 10 years old, hopefully he got it running years ago and either blew it up or moved on to something else.
 
360 LA had those dished pistons get rid of them, up compression and...voila! however, this is what I don't like about the 70s 318 and 360 (low compression) but at least the 360 has the heads. 318 you re always going to throw 360 heads on one so why not just get a 360 start with the low compression and the heads, throw some pistons in it and be done... I never get the guys spending hours porting 318 heads thinking something will come of it.:)
 
@PROSTOCKTOM

What length rods are available for the 340?
Does Molnar offer cranks greater than 4.00 for the small block?
 
Dartswinger70 said:
360 LA had those dished pistons get rid of them, up compression and...this is what I don't like about the 70s 318 and 360 (low compression) but at least the 360 has the heads. 318 youya re always going to throw 360 heads on one so why not just get a 360?
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Some like the small engine challenge, others are simply working with what they got as well as a possible limited spending amount.
The adage of bigger is better is what you present but I wonder why if such is the case, why didn’t you recommend a stroker at maximum CID?

:lol:
 
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