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Re: 340 verses 360 [Re: Kindafast] #196462
01/18/09 06:50 PM
01/18/09 06:50 PM
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Kalispell Mt.
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HotRodDave Offline
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Back in the day those heavy 340 pistons were stressing those steel cranks something fierce. 360 pistons were a lot lighter and easier on cranks. Because of the higher cubes the 360 did not have to rev as high to make the same power, also easier on cranks.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: 340 verses 360 [Re: Kindafast] #196463
01/18/09 07:06 PM
01/18/09 07:06 PM
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Posts: 2,327
Glendale, AZ
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69L78Nova Offline
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Quote:

I shyed away from them soley because of the cast cranks. Small blocks were made to turn upstairs and I just didn't feel safe turning a cast crank up where I could overcome the torque loss of a smallblock




Ive run my CAST crank in my 360 up to 7700rpm for 6 years with not one problem when it was in my race car. All I did was use H-beam rods, and had it balanced...and that was with KB hypereutectic pistons. Ive not the only one in this area to buzz a stock crank 360 up that highh for that long. Its still running to this very day in my Barracuda with the same bearings I put in it in 2001. They looked like brand new when I put the motor in my Cuda, only now with a much smaller cam. At any rate, its BS. I wouldnt go and put a big shot on it or hit it with big boost running those RPMs, but for a N/A budget small block, it works for me and MANY other people.


1969 Nova
454/M21/3.31
Mild mid-11 second weekend cruiser

1994 F150 XLT Super Cab 2WD
5.0/4R70W/3.55
(Daily driver)
Re: 340 verses 360 [Re: MoparforLife] #196464
01/18/09 07:08 PM
01/18/09 07:08 PM
Joined: Oct 2005
Posts: 1,927
Seaford, Va
Kindafast Offline
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Ok I see Im beating a dead horse here. One last question if a 360 engine setup is so much better that a 340, why are all the race blocks based on the 340 instead of the 360? Making that limited power improvement at low end will get far overshadowed by the ability of the 340 to continue to make power up to 8000 rpm. I did not want to start a heated discussion nor will I continue being a part of it. These are just my opinions .


6.50 @105.26
Re: 340 verses 360 [Re: dodger1] #196465
01/18/09 07:28 PM
01/18/09 07:28 PM
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Posts: 892
USA
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krw71ragtop Offline
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Quote:

Im wondering if a 340 would be a better choice to build a moderate hp engine, I have seen 340s for five hundred with heads 360 are cheaper but will I need to buy better heads anyway and really not save any money. thanks for your advice



I just got my 340 (416) fired up last summer. Now planning on doing a 360 (408). Ive done research on both stroker kits and from what I see there is not a big difference in price. Mancini has several different kits for the 360 but its only $60 cheaper than the 340 kit. I looked in the Hot Deals section here and looks like Hughes Engines has a stroker sale going on. Not sure what the price difference is between the 340 and 360 kit.
My point is you are not going to save thousands of dollars by building a 360. You can buy a 340 block for $350 here on Moparts. If you can get a 360 for $50 you have saved $300 plus the $60 you saved on the stroker kit from Mancini for a grand total of #360. The rest of the parts for the build will cost the same for both motors.
I'll take a 340 any day over a 360. To me its like comparing a 426 to a 440. The 426 is Legendary!
Either way cost will be close to the same and you will not feel the horse power difference in the seat of your pants between the 2 builds.
And if anybody wants to prove me wrong on the cost difference show me your proof. I have cash for that 408 kit.

Re: 340 verses 360 [Re: HotRodDave] #196466
01/18/09 08:09 PM
01/18/09 08:09 PM
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Upper Midwest
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Quote:

Back in the day those heavy 340 pistons were stressing those steel cranks something fierce. 360 pistons were a lot lighter and easier on cranks. Because of the higher cubes the 360 did not have to rev as high to make the same power, also easier on cranks.



The above is basiacally a myth -- in 72 the 340 started using cast shafts and still had no problems.

Re: 340 verses 360 [Re: MoparforLife] #196467
01/18/09 08:28 PM
01/18/09 08:28 PM
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Kalispell Mt.
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HotRodDave Offline
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In 72 they also ran lighter pistons and lower compression more restrictive exhausts and not many people leaned real hard on those cranks except a few super stock guys who would push there luck real hard to gain the smallest amount of ET.

Fact is a hevier piston is harder on a crank and rods than a lighter piston, any one who argues that is or or mabey


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: 340 verses 360 [Re: HotRodDave] #196468
01/18/09 08:51 PM
01/18/09 08:51 PM
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Upper Midwest
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So is spinning an engine past it's effective RPM range.
I was there in the day, and the ones that had a problem were teh ones that thought that they had to spin the Hell out of the engines and floated them out and didn't maintain them worth a dang anyway. Heck they were under warranty run the P out of them. There was no sense to spinning them like that they were peaked at or just before 6 anyway.
Quote:

Fact is a hevier piston is harder on a crank and rods than a lighter piston, any one who argues that is or or mabey


Won't argue that point but those cast shafts will take anything a those 340's would throw at it and then some.

Re: 340 verses 360 [Re: MoparforLife] #196469
01/19/09 07:51 AM
01/19/09 07:51 AM
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Posts: 8,162
USA
3
360view Offline
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Just for kicks
since I already had the
Performance Trends Engine Analyzer 3.2b software with 1995 Magnum 360V8 factory specs,
I changed the short block to 3.31 stroke and 4.17 bore to simulate a 340 style short block, but with the same displacement. (I realize 360 blocks can't be overbored that large)

Torque went up 6 ft-lbs at 3200 rpm and
WOT Horsepower went 5 hp at 4000 rpm
with the shorter stroke and larger bore.

Willem Weertman's write up of the creation of the 360 in his book:

http://www.amazon.com/Chrysler-Engines-1...5606&sr=1-1

seems to indicate it was all about low cost, and he seemed almost apologetic about the external balancing.

I have wondered why 3.88 inches was chosen as the stroke of the V10. Weertman writes that this stroke length was ordered by Bob Lutz simply to bring the displacement to an even 8 liters.

The story in the book about how the first v10 was built by a specialty shop by brazing on 2 more cylinders to a 360 v8 was interesting.

Re: 340 verses 360 [Re: Kindafast] #196470
01/19/09 10:10 AM
01/19/09 10:10 AM
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick Offline
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Grand Haven, MI
Quote:

Ok I see Im beating a dead horse here. One last question if a 360 engine setup is so much better that a 340, why are all the race blocks based on the 340 instead of the 360? Making that limited power improvement at low end will get far overshadowed by the ability of the 340 to continue to make power up to 8000 rpm. I did not want to start a heated discussion nor will I continue being a part of it. These are just my opinions .




a 340 & 360 are essentially identical block wise except for main bearing journal diameter...the smaller main bearing will be less parasitic friction.....but you could get the R3's in both 340 and 360 main size.

the biggest reason a stock 360 won't rev like a stock high comp 340 is the stock cam build a 340 and 360 equally--same cam, similar reciprocating weight in the rod/piston combo, compression, heads, intake, carb, etc, a 360 will about 5-8% more torque over a 340 (due to increased displacement) at a very slightly lower RPM, and it will make more HP if the combo wasn't maxed out on the 340. and the 360 will rev just as quick as the 340.


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: 340 verses 360 [Re: 360view] #196471
01/19/09 10:16 AM
01/19/09 10:16 AM
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick Offline
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Grand Haven, MI
Quote:

Just for kicks
since I already had the
Performance Trends Engine Analyzer 3.2b software with 1995 Magnum 360V8 factory specs,
I changed the short block to 3.31 stroke and 4.17 bore to simulate a 340 style short block, but with the same displacement. (I realize 360 blocks can't be overbored that large)

Torque went up 6 ft-lbs at 3200 rpm and
WOT Horsepower went 5 hp at 4000 rpm
with the shorter stroke and larger bore.

Willem Weertman's write up of the creation of the 360 in his book:

http://www.amazon.com/Chrysler-Engines-1...5606&sr=1-1

seems to indicate it was all about low cost, and he seemed almost apologetic about the external balancing.

I have wondered why 3.88 inches was chosen as the stroke of the V10. Weertman writes that this stroke length was ordered by Bob Lutz simply to bring the displacement to an even 8 liters.

The story in the book about how the first v10 was built by a specialty shop by brazing on 2 more cylinders to a 360 v8 was interesting.




I've seen an article a few years ago which was a comparison of 2 LS1 motors in the 400 inch range, IIRC. one was based off a corvette 5.7 with a stroker crank and essentially stock bore, the other based of the 5.7 with a stock stroke and wet sleeves to do an all bore big inch motor. they were built with identical heads, cam, induction, etc. like your engine simulator results, HP and torque were virtually identical, with negligible differences (within 1-2% of each other, just like your computer simulation).

if I had to swagger the slightly higher numbers were probably due to the simulator accounting for valve shrouding.


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: 340 verses 360 [Re: patrick] #196472
01/19/09 10:19 AM
01/19/09 10:19 AM
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick Offline
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Quote:

Quote:

Ok I see Im beating a dead horse here. One last question if a 360 engine setup is so much better that a 340, why are all the race blocks based on the 340 instead of the 360? Making that limited power improvement at low end will get far overshadowed by the ability of the 340 to continue to make power up to 8000 rpm. I did not want to start a heated discussion nor will I continue being a part of it. These are just my opinions .








a 340 & 360 are essentially identical block wise except for main bearing journal diameter...the smaller main bearing will be less parasitic friction.....but you could get the R3's in both 340 and 360 main size.

the biggest reason a stock 360 won't rev like a stock high comp 340 is the stock cam build a 340 and 360 equally--same cam, similar reciprocating weight in the rod/piston combo, compression, heads, intake, carb, etc, a 360 will about 5-8% more torque over a 340 (due to increased displacement) at a very slightly lower RPM, and it will make more HP if the combo wasn't maxed out on the 340. and the 360 will rev just as quick as the 340.

realistically if building a stroker, the cost difference is negligible, the 360 cranks are slightly cheaper, pistons nearly identical cost, and rings for a 4.03 bore are cheaper, especially when you start getting into the thinner ring packs.....

now if you plan on running a hydraulic roller cam, a 360 can be significantly cheaper if you start with an '89-up block, as you can use OEM lifters which are about $120/set, vs. the retrofit lifters that run in the $450-550 range.


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: 340 verses 360 [Re: patrick] #196473
01/19/09 04:22 PM
01/19/09 04:22 PM
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Kalispell Mt.
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HotRodDave Offline
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Patrick the 4bbl 360s had the same cam as the high comp 340 but no high compression and lousy exhaust flow and leaner carb settings for emmisions.

The closest you can find them in stock form for comparison is a bone stock 73 340 in an A-body with low comp lousy exhaust emmisions calibration and compare it to a 74 360 in an A-body. The 74 360 will woop the 73 340 every way imaginable.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: 340 verses 360 [Re: MoparforLife] #196474
01/19/09 04:55 PM
01/19/09 04:55 PM
Joined: Jul 2005
Posts: 1,044
minnesota
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president61 Offline
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minnesota
Quote:

No Forged 360 crank - Big deal - Mopars are not noted for crankshaft breakage. Forged or cast.
The 360 is not a high RPM oriented engine like a 340. They make it at a lower RPM.
Like I said if the 360 would have been made during the non emision ere it would have been 'the small block'. The 340 would not hold a candle to it.



EXACTLY! THERE IS NO SUCH THING AS A NON PERFORMANCE 340 SO THEY WERE ALWAYS CONSIDERED BETTER THAN THE 360. UNTIL RECENTLY 360S WERE CONSIDERED JUNK BECAUSE FOR THE MOST PART THEY WERE PUT IN FULL SIZE CHRYSLERS WITH PATHETIC COMP RATIOS AND FIBER TIMING CHAINS. I'D BUILD THE 360 WITHOUT HESITATION

Re: 340 verses 360 [Re: president61] #196475
01/19/09 05:14 PM
01/19/09 05:14 PM
Joined: Jan 2003
Posts: 1,359
Buzzard County, FL
IronWolf Offline
pro stock
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Buzzard County, FL
You are correct, Mr. Caps.

Hoever, the next time you pull into a "jiffy Mart" with a small block, it's best to tell the skell that you are packing a "340" (=respect) vs a "360" (=grandma's sedan). That's the legend. Whence the legend ? I dunno. Except the original 360's came in 4000 pound luxo-barges with 2-barrels and 2.76 rear end ratios. LOL.

Re: 340 verses 360 [Re: IronWolf] #196476
01/19/09 05:19 PM
01/19/09 05:19 PM
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Upper Midwest
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Well, for the day the 360 cop cars weren't real slouches.

Re: 340 verses 360 [Re: MoparforLife] #196477
01/19/09 05:31 PM
01/19/09 05:31 PM
Joined: Jan 2003
Posts: 1,359
Buzzard County, FL
IronWolf Offline
pro stock
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Buzzard County, FL
Right.

But the "perception" is that the 360's were slouches, per my example.Granny's 4-door Whatever.

I run a 360 and am very happy with it - but it's not stock, and it's not running in a '72 Crestwood Station Wagon with low-po everything.

Re: 340 verses 360 [Re: HotRodDave] #196478
01/19/09 05:32 PM
01/19/09 05:32 PM
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick Offline
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Quote:

Patrick the 4bbl 360s had the same cam as the high comp 340 but no high compression and lousy exhaust flow and leaner carb settings for emmisions.

The closest you can find them in stock form for comparison is a bone stock 73 340 in an A-body with low comp lousy exhaust emmisions calibration and compare it to a 74 360 in an A-body. The 74 360 will woop the 73 340 every way imaginable.




IIRC only the E58's had the 340 cam, and at that it was the milder auto tranny cam, not the '68 4 speed stick. non E58 engines I thought had the same cam as the 2bbl 360's (which was ~.410 lift, 250ish adv. duration)


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: 340 verses 360 [Re: IronWolf] #196479
01/19/09 05:49 PM
01/19/09 05:49 PM
Joined: Jan 2003
Posts: 1,359
Buzzard County, FL
IronWolf Offline
pro stock
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Posts: 1,359
Buzzard County, FL
A better idea is to tell the people at the "Jiffy Mart" that you are running a 340 ? How in the heck could they dispute this ? Instant respect (ooh,forged crank, "high compression") !!

Do they imagine the lightweight Dusters/Demons of yore ? I think so ! Because the smallblock cudas/challengers were no world beaters (DAMHIK).


Nevermind the importance of body-weight to HP ratio, drag coefficents, center-of-gravity, parasitic mechanical drag, etc, etc) Nah, it's the legend, and I cannot figure whence the legend came. When, where ?

On the street perhaps ? I have heard rumors of 340 Dusters/Demons waxing Roadrunners/Superbees.
Dunno.

Re: 340 verses 360 [Re: dodger1] #196480
01/19/09 05:53 PM
01/19/09 05:53 PM
Joined: Jan 2003
Posts: 9,826
las vegas
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las vegas
if we get back to the orginal question about which is better TODAY....

then we throw out all the BS about which one had higher compression...lousey intake carb and exhaust..cause i doubt that he would be using stock intake and exhaust...and the compression is limited on both engines cause of lousey gas..


So ToDAY with cheaper and lighter pistons available, cheaper rings, and with the same intake/cams for both...

the 360 wins...


Tony

70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
Re: 340 verses 360 [Re: IronWolf] #196481
01/19/09 06:06 PM
01/19/09 06:06 PM
Joined: Jan 2003
Posts: 1,482
Lake Orion, MI
goldduster318 Offline
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Lake Orion, MI
The 360, especially in magnum form, ROCKS! Those MP 300hp 360 crates were nothing more than pickup truck engines with an LA timing cover, car oil pan, dual plane, and conventional ignition. Even had 9:1 compression and an under 0.400" lift cam. 300+hp and 375 lb-ft...that's a little bit better than real world numbers on a stock 340. Real world, 360's are a lot cheaper, especially since you can still find good bottom ends.


'70 Duster 470hp 340/T56 Magnum/8 3/4 3.23 Sure-Grip
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