Posted By: tee-john
340 or 360 Which one is a better build???? - 09/27/09 12:17 PM
I have a 68' Barracuda fastback with a 318. I need to do a transplant and I don't know much about Mopar engines as far as to know which engine would give me the best h.p. and torque. Fitment is also a small issue. This is a street car, but I don't mind strip style power. Any info would be helpful. I will cross the tranny and rear end issue later. The car is drivable now so I have time to do my build. If a 340 builds better and runs better than a 360 or visa versa is what I am trying to find out. Thanks guys.
Posted By: MoparforLife
Re: 340 or 360 Which one is a better build???? - 09/27/09 12:53 PM
Build your 360. They are alot easier to find than 340's which are in high demand by restorers so cammand a higher price.
IMO if the 360 had been built in the same time frame as the 340 with the samde basic specs as the 340 of the time it would have been the engine of choice, not the 340. Been like comparing the 361 4 barrel to the 383 4 barrel.
Posted By: 440abody
Re: 340 or 360 Which one is a better build???? - 09/27/09 01:10 PM
360; just for the exact reasons that Moparforlife stated. They are far more plentiful, and in my opinion there are more parts available(stroker kits etc). Besides this also opens up an other possibility of using a Magnum motor vs the LA. Besides if you decide to build the car into a clone(tribute) a 360 visually will look identical to a 340.
Posted By: 360view
Re: 340 or 360 Which one is a better build???? - 09/27/09 02:23 PM
the 340 versus 360 debate can go on endlessly,
but it boils down to 'what stroke length' is best?'
In this ongoing quest
there is a recent development:
When Ford recently designed a new V8
they used an even longer [edit] stroke than 3.58 inches and more similar to dodge V10 selection:
http://www.themustangnews.com/carnews_09/0909-ford-6.2.v8-engine-137.htmdoes the engine care what the stroke is,
or does it care what the ring friction is?
Posted By: 70Cuda383
Re: 340 or 360 Which one is a better build???? - 09/27/09 02:35 PM
dollar for dollar spent, the 360 will ALWAYS make more power than the 340 when building a bare block.
--if you put the same cam, heads, intake and carb on the 340 and the 360, built the short blocks with stock cranks, rods and use pistons that give you an equal compression ratio between the 2, it's a no brainer...the 360 will win.
spend your money on a 360 stroker.
408 is the common stroker size, and can make very good power and still be streetable. lotta guys running them in Dakota's dipping into the 12s with a 4,000+lb truck, and still passing emissions with them.
Posted By: pnypwr
Re: 340 or 360 Which one is a better build???? - 09/27/09 03:00 PM
in stock form a 340s better, your 318 parts will bolt right on...eg oil pan, tans t. converter if its an forged crank 340, flywheel if its a std shift. you can go further with a 360 in the $$ dept because they are more plentiful. it really depends on what your looking to do
Posted By: 2boltmain
Re: 340 or 360 Which one is a better build???? - 09/27/09 03:07 PM
340s are great but c'mon, how many are out there REASONABLY priced? 340s made from 1968 to 1972-73. 360s made from 1972 to....2002
Posted By: Mr.Yuck
Re: 340 or 360 Which one is a better build???? - 09/27/09 03:09 PM
starting from scratch? 360
Posted By: dodgefarmer
Re: 340 or 360 Which one is a better build???? - 09/27/09 03:19 PM
Seeing as how your into a build anyway, and are going to have to buy a rebuildable core. I would just stroke the 318. Works out to 390 cube. Same money.
Randy
Posted By: CJK440
Re: 340 or 360 Which one is a better build???? - 09/27/09 04:39 PM
a .040" over 360 is just a 340 with a stroker crank.
Posted By: pyrogen
Re: 340 or 360 Which one is a better build???? - 09/27/09 11:01 PM
in theory, more displacement provides more potential power.
I have to ask, Do you already have an engine to build or are you trying to determine which one to purchase to build?
Posted By: tee-john
Re: 340 or 360 Which one is a better build???? - 09/28/09 01:17 AM
There is a 360 for sale in the area so I gave it a thought. So basically I am starting from scratch.
Posted By: tee-john
Re: 340 or 360 Which one is a better build???? - 09/28/09 01:29 AM
Yeah I will have to buy something to build, and I have not given any thought to stroking the 318. I didn't know if it would be worth it. I would like to be in the 400-450 hp range with plenty of torque. Can this be reached with the 318 stroked out. If so where can I find info on what to use to do the job? Thanks.
Posted By: dodgefarmer
Re: 340 or 360 Which one is a better build???? - 09/28/09 01:29 AM
Cost of engine plus cost of crank grind = cost of 4" stroke crank for 318.? All other parts and labor will be the same.
Randy
Posted By: patrick
Re: 340 or 360 Which one is a better build???? - 09/28/09 12:26 PM
start with a late model magnum 360. better heads, factory roller cam, you can build a hydraulic roller cammed motor much cheaper using factory parts.
Posted By: jimmy71demon
Re: 340 or 360 Which one is a better build???? - 09/28/09 12:34 PM
i am almost done building my 340 stroker. my 340 block was done so i had to find another one (i wanted to stay with the 340 block). it proved to be much harder than i thought to find a 340 block that was .020 over or less. (when its pretty much raining 360's) plus it was pricey. bang for ur buck ull prolly find a 360 out of a truck or a van or something for a hell of a lot cheaper than a 340. after that i dont c there being much difference in price for parts.
p.s. im told my stroker with my mildly ported J heads and .488 lift comp cam should put out somewhere around 425-450 hp
Posted By: RapidRobert
Re: 340 or 360 Which one is a better build???? - 09/28/09 02:16 PM
As said w stock strokes definitely a 360 vs a 340 for the reasons stated. With the 4" stroke there's only an 8 ci difference between the 2 (30 over 360 vs a 30 over 340) so I'd still go w the cheaper 360 block unless a person already has a 340 block on hand.
Posted By: Reggie
Re: 340 or 360 Which one is a better build???? - 09/28/09 03:47 PM
The 400 HP 318 specs are
here. One build made 400 HP at 6,150 RPM and 382 lb/ft torque at 4,900 RPM and the other one made 406 HP at 5,900 RPM and 408 lb/ft peak torque at 4,700 RPM. After all of the shouting and hype to sell magazines, NONE of those 400 HP 318 builds resulted in torque figures as high as a basically stock Magnum 5.9 with just bolt-ons:
Mopar M1 single plane intake
Barry Grant Mighty Demon 750 CFM carburetor
TTI headers
The 5.9 produced 345 HP at 4,600 RPM and 426 lb/ft of torque at 3,800 RPM - more torque at an average of 1,000 RPM lower than both 318 builds.
Build a 360. Get a Magnum 5.9 as Patrick mentioned (easier to find) or even snag a 89-92 LA roller 360 block if you run across one. They are probably harder to find than the later Magnum blocks, but all of the later Magnum roller hardware interchanges, plus you have the option of using either Magnum or LA-style heads on it. Casting numbers to look for are 4315830, 53006921 and 53020006.
Posted By: joedust451
Re: 340 or 360 Which one is a better build???? - 09/28/09 07:28 PM
I will say this, when i was looking for a 360 to build, most everyone said go Magnum, so i found one, then after purchasing it & wanting ideas, most said i should have built an LA, then as you will find out, ALL those magnum heads WILL be cranked, didn't find out this info untill after i made my purchase, not knocking anyone, i'm happy i got it, i do like the fact it has higher compression & a lighter rotating assembly, so thats a plus, but the heads are PURE JUNK, not that they don't flow better, but i will not build (or assemble) an engine with cracked heads period, i don't care if they don't leak, so i threw them away, bought some RHSs from Hughes for 875.00, so plan on another set of heads. Someone did a build on a 300hp 360 magnum, left the lower end stock (the 300hp 360 magnum "crate" has the same components as the production 360 magnum), they installed a cam, eddy heads, & intake/carb/ignition/headers, it made 458 HP, forgot what the torque was, but still, pretty impressive.
Mine should be around 375 HP with a .500 lift cam & RHS heads with the stock bottom end.
Posted By: 70AARcuda
Re: 340 or 360 Which one is a better build???? - 09/28/09 07:52 PM
Posted By: dodgefarmer
Re: 340 or 360 Which one is a better build???? - 09/28/09 08:04 PM
A 30 over 318 with a 4"stroke is 390.6 cid. There is no 360 with equal heads, cam, and compression, ever going to out work it (it's 30 cubic inches smaller). As stated any magnum engine will need heads, and any LA 360 is going to require the same investment as your 318 with the stroke crank. If you build this to the 400 horse 318 specs with the stroke crank you will easily meet your goals and then some. Check summit for the cost of a 318/340 cast 4" stroke crank. Then check with your machine shop on the cost of a crankgrind, add that to purchase price of the 360,and compare your options
Randy
