340 v 360 street help

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KramerSwinger70

KramerSwinger70

70 Dart Swinger360
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curreently lookin around for a 340 or 360 engine for my 70 dart (gotta swap out my /6 for some v8 muscle...no offence /6 guys). im curious, as no ones really told me the difference. so, besides obvious displacement, what are the advantages of a 340 over a 360 (or visa versa)? im goin to run it as a street engine so no more than 270hp is neccesary and i kno theyr both very capable of that. is gas mileage any better from one of them? easier/cheaper to build and rebuild? thanks!
 
Get whats available for a reasonable price. Autozone could have both available with prices with and without a core. The 340 will take a 60 over bore but the factory only recommends a 20 over for the thin wall castings 360 engines built after 1974. Stay away from the Mopar crate engines they are prone to failure. 318s are probably easier to find parts are available at reasonable cost and for a driver they are excellent engines.
 
360 will likely be cheaper and easier to find. With the longer stroke and 20 more cubic inches, it will also be more responsive on the street with less modifications needed.
 
I'm with Locomotions description and idea.

The longer crank throw will add a nice amount of torque down low for easy of getting that car moving.

In my old '79 Dodge Magnum, the 360 was stock minus the dual exhaust off the manifolds @ 2-1/2 with an "H" pipe, Carter 625 cfm on top of a iron intake and a MSD triggering a junkyard distributor.

With 26 inch tires on the back and 2.76 gear, I could get 20 mpg Hwy.

Tune the carb well and time it right with the MSD, you'll go far on a gallon of gas for a old car.
 
the 360 will be cheaper to find and build...

have a 78 block that is bored .040 that has run 10.80 in barracuda...so that thin wall statement is a urban myth...
 
Here is a good article on the 318
http://www.carcraft.com/techarticles/ccrp_0401_mopar_318_engine/index.html

I think CarCraft or Hot Rod has a good feature build with the 318 in the latest issue. They are great motors and the Magnum engines offer some great features too. I have seen then for less then $250. A low buck rebuild, cam, intake, carb and headers will net you an easy 300HP.
Wayne
 
I don't think it's a issue of building a 318, just pro's and con's between the 340 and 360. For a street engine to run around in and go far, ethier will do great. The 360 is just cheaper with more torque.
 
As stated,. the 360 is a lot cheaper and easier to find than the 340, has 20 more cubes to start with, and will respond the as the 340 with the same parts added. It also has better bottom end torque than the 340 for street use.
 
well from what i gather here, everyone suggests the 360 over the 340 in every aspect of it then haha. cheaper easier and faster. sounds like a good formula to me!
 
Interesting comments in this thread! I have a poll going on a thread I started concerning the value of a 340. Poll stated (1) gotta have a 340; (2) forget the 340 go with a 360; (3) forget the 340/360, make it a big block; and (4) keep the slant/273/318. Results so far: out of 155 votes over half (84) stated gotta have a 340, 33 for a 360, 23 for a big block and 15 for everything else.

Disclaimer: your smile may vary depending on your choice!
 
340's are cool...but get a 360...on the previous thread, i think there was an option to vote for a 408 stoker, which i picked. anyways, 360 has my vote on this one...340's are too hard to find, and too expensive....why pay more for less cubic inches?
 
mopardude318 said:
340's are cool...but get a 360...on the previous thread, i think there was an option to vote for a 408 stoker, which i picked. anyways, 360 has my vote on this one...340's are too hard to find, and too expensive....why pay more for less cubic inches?
Click to expand...

u make a valid point, my good sir haha
 
73charger said:
well from what i gather here, everyone suggests the 360 over the 340 in every aspect of it then haha. cheaper easier and faster. sounds like a good formula to me!
Click to expand...

73charger,
For strait cubes, the 360 would be the way to go.

I am out of the Modesto area. Modesto craigs list has a complete 360 for sale in the auto parts section for 100.00. Might be worth checking on if your local core dealer wants too much.

You stating that 275 would be plenty enough power for you; you might want to re-consider the 318. We had a proud 318 in a dodge dart just walk away from my buddy's sb400 4speed corvette in strait line performance.

Don't know what your budget is....may want to consider the 318 stroker. 390cid I think would be your final displacement. More experienced builders on this site could steer you that way if you choose.

Currently building my own 360. The "site" has been more than helpful for me.

Good luck.
 
360, either LA or magnum, i went the magnum route this time around, i really like it, like said, the extra cubes & stroke are worth it.

I also disagree on the .020" myth on the 360 blocks, even though mine was a mid 70 block, i bored it .060" & it ran like a dream.

100_0958.jpg
 
360 all the. Way cheaper to buy, they make all the same parts for either motor, and on the street I prefer the extr tq and cubes. Leave the 340 for the resto guys
 
My first engine in the Duster was a 340. After I spun a rod bearing in it I used a Mopar crate 360 shortblock because I needed a running engine in a week and I used the same cam, heads, intake etc. The 340 did have H beam rods and light weight Ross pistons in it though while the 360 has hypereutectics and stock rods, everything else was the same.

They ran within .02 of each other. The difference was I could take the 5.13 gear out I had in it with the 340 and put in a 4.88 for the 360. I twisted the 340 to 8000 rpm, the 360 to 7200.

Easier on parts, cheaper to build and much easier to find. What's not to like?

I did like the top end charge of the 340 though, that thing would really pull on the top end but since this a street car you're building that isn't a concern for you.
 
Your right about that top end charge of a 340 Mr. Jones, a heck of a runner it is.
 
360moparjunkie said:
73charger,
For strait cubes, the 360 would be the way to go.

I am out of the Modesto area. Modesto craigs list has a complete 360 for sale in the auto parts section for 100.00. Might be worth checking on if your local core dealer wants too much.

You stating that 275 would be plenty enough power for you; you might want to re-consider the 318. We had a proud 318 in a dodge dart just walk away from my buddy's sb400 4speed corvette in strait line performance.

Don't know what your budget is....may want to consider the 318 stroker. 390cid I think would be your final displacement. More experienced builders on this site could steer you that way if you choose.

Currently building my own 360. The "site" has been more than helpful for me.

Good luck.
Click to expand...

Thanks for the hint! ill have to see of my dad will go with me to check it out! any idea of the condition of it? do you live by there? im up in the Santa Rosa area so its quite the drive for me, maybe you could scout for me? id really appreciate it!
 
73charger said:
lots of people have suggested a 318, but i jus plain dont want one.
Click to expand...

Dont kid yourself. I am putting together a 349 based off of a 318 block right now. With ALL new parts including heads and machine work over a 9 month period I will have Under 3k in the engine complete minus carb. It will put down at least 425 HP and great TQ curve. That will SCOOT your car very quickly down the road no doubt!
 
Mad Dart said:
Dont kid yourself. I am putting together a 349 based off of a 318 block right now. With ALL new parts including heads and machine work over a 9 month period I will have Under 3k in the engine complete minus carb. It will put down at least 425 HP and great TQ curve. That will SCOOT your car very quickly down the road no doubt!
Click to expand...

im not kdding myself. im an 18 year old kid (oh the irony!) and this is my daily driver..who needs a 400hp grocery gettin, school drivin, 6mpg dart!? not me! i want mid 200hp range and decent mileage for a 70s car. my dart is gonna be a cruiser, not a drag car. just like my uncles 73 charger. 400 BB 260hp...cruiser! end of story. and 3k is alot of money for a daily driver engine, especially wen you wokr for $8.50 per hour.

for you application im sure 425hp is awesome, and i applaude that, its very respectable. just not at all what i want for my car
 
73charger said:
im not kdding myself. im an 18 year old kid (oh the irony!) and this is my daily driver..who needs a 400hp grocery gettin, school drivin, 6mpg dart!? not me! i want mid 200hp range and decent mileage for a 70s car. my dart is gonna be a cruiser, not a drag car. just like my uncles 73 charger. 400 BB 260hp...cruiser! end of story. and 3k is alot of money for a daily driver engine, especially wen you wokr for $8.50 per hour.

for you application im sure 425hp is awesome, and i applaude that, its very respectable. just not at all what i want for my car
Click to expand...


Then just drop in a running 360 with exhaust manifolds & be done.
 
73charger said:
im not kdding myself. im an 18 year old kid (oh the irony!) and this is my daily driver..who needs a 400hp grocery gettin, school drivin, 6mpg dart!? not me! i want mid 200hp range and decent mileage for a 70s car. my dart is gonna be a cruiser, not a drag car. just like my uncles 73 charger. 400 BB 260hp...cruiser! end of story. and 3k is alot of money for a daily driver engine, especially wen you wokr for $8.50 per hour.

for you application im sure 425hp is awesome, and i applaude that, its very respectable. just not at all what i want for my car
Click to expand...

Mid-200 HP range is a piece of cake for even a 273, let alone a 318/340/360. IMO if you go with a 318 built right you'll get all the power you need PLUS a couple extra MPG over a 360. I'm 18 as well and money is also extremely tight for me so I understand your concerns but you can build a 275 HP 318 that gets 20+ MPG with the right gearing, for little over $2000.
 
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