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Re: Is the 360 an inherently inefficient engine?
[Re: dodgedon]
#1622042
05/20/14 02:38 AM
05/20/14 02:38 AM
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Joined: Mar 2003
Posts: 18,678
Fresno, CA
Jim_Lusk
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I Live Here
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Posts: 18,678
Fresno, CA
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Quote:
The 360's in trucks that i have seen always had lower gears in them. 3/4 and 1 tons had 4:10 and lower gears. If it was a half ton it had 3:91... The 318's I have seen in 1/2 tons in the 70/80's had 3:23 gears and in the 90's and up had 3:55's Those low gears realy hurt MPG.
Many years ago a friend of mine had a 73 1/2t Power Wagon short bed with a 360 and 3.55s. That truck would run, especially after the motor build and 4 barrel...
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Re: Is the 360 an inherently inefficient engine?
[Re: 360view]
#1622043
05/20/14 04:41 AM
05/20/14 04:41 AM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
Pale_Roader
OP
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OP
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the frozen wastes...
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Quote:
You ought to clarify what you mean by "inefficient".
Yes, i should have.
Here are my stipulations for this project:
1 - MUST be a V8.
2 - BEST gas mileage possible (and dont lecture me on driving or hypermiling) By this i mean hammering on a 4.6L mod will still get me past far more gas stations than hammering on a 440 Mopar in the same car with the same gearing.
3 - Must make decent power. Now 'decent' for me, at this stage anyways means 300HP net or close to. That'll go fast enough for my 3000lb daily driver.
The PERFECT plant for this project would be a 99-up 4.6 DOHC mod. 320HP net (350 as installed), high-20's highway MPG, lighter than a /6, sounds amazing. I dont have the money for this.
Right now, i'm very time-limited and poor as dirt. HAD THEY MADE ONE... (read: i'm NOT making one) a 273 Magnum would have been interesting. The 318 Magnum is the closest CHEAP, EASY bolt-in i can conjure up. The intake and exhaust issues will be addressed with the install (Doug's headers and RPM air-gap/Holley 4bbl).
Quote:
This beefed up lower end also makes it about 57 lbs heavier than a 318,
Can anyone else confirm this? I have NEVER read about any smallblock Mopar being heavier than another... and certainly not 57lbs. I cant see it. Yeah... the crank is bigger at the bearing, but on the 318, the webs would make up the same space. The 400 is around 20lbs heavier than the 440, even the 426 Hemi cant be 57lbs heavier than the 426 wedge. Theres just no way.
For 57lbs difference, i'd go with the 318 even if i lost 50HP. Hell, i'd go with the 318 if it was 20lbs lighter. Weight means everything in this project.
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Re: Is the 360 an inherently inefficient engine?
[Re: RUNCHARGER]
#1622044
05/20/14 05:09 AM
05/20/14 05:09 AM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
Pale_Roader
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Quote:
I bought a new 318 magnum in my 92 pickup and that thing hauled butt, So I made the mistake of getting another 318 Magnum in my new 96 pickup, that truck was a dogg,
Sheldon
So why was this? Heavier truck (everything always gets heavier, year to year)? Different gears? More accessories in the 96? Heavier drivetrain behind the 96?
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Re: Is the 360 an inherently inefficient engine?
[Re: GY3]
#1622045
05/20/14 05:15 AM
05/20/14 05:15 AM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
Pale_Roader
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Quote:
Low compression on the 360 when compared to the 340's is the culprit.
Yeah... whole different animal, thats why i didn't even mention the 340. Plus... junk heads, no roller cam, and i'm not paying a 340 premium.
Quote:
I have a 360 with 9.5:1 and a 750 3310 Holley. It's as efficent as you're gonna get in a 5,600 lbs. Powerwagon with full time 4wd. It does get better mileage than the 318 2 bbl. it replaced.
11 mpg average for the 360 and 9 mpg average for the 318 with LOTS more grunt and towing capability.
Well, at 5600lbs i guess so. Thats WAY too much haul for a 318.
With a CR comparable to a 68-70 340 though, i'd love to see them both in a car and see what happens....
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Re: Is the 360 an inherently inefficient engine?
[Re: dogdays]
#1622046
05/20/14 05:26 AM
05/20/14 05:26 AM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
Pale_Roader
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Quote:
I had some friends who were driving government fleet vehicles, Dodge Durangos, it was widely known and they confirmed that the 5.9 Mag got better mileage than the 5.2.
That is very surprising, and even here far the exception. Interesting. Then again, thats a heavy heavy rig. Past a point i think with a 318 you're just flooring it to get it out ov the driveway...
Quote:
Now there is no earthly reason why a 360 would have different economy characteristics than a 350 chevy, but they seemed to. During the '70s, neither one had much compression and neither had a cylinder head with squish.
I agree... you would think that with all the talk about Mopar design and efficiency, the 360 would pass more gas stations, but i've always known 350's to be decent on gas. My Chevy friends rave about them.
Quote:
If you have a 5.2 Mag on a stand I say build it. The reports on them from Board members is that with proper tuning and a few hotrod parts they will make power equal to an LA 360 but with quite better mileage. That's for street engines.
If you really want more power stick a 4" crank in the 5.2 and go to town.
Dont have it yet, but i found a nice one and its close to home and cheap. No need and no want for a stroker. I dont need 400cid to win races.
Quote:
Before I'd put a 5.2 on the shelf for a 5.9, I'd find a G3 Hemi. That's significantly lighter and stronger, also more efficient.
R.
Well... if i had the time and money to do a full custom install with a completely foreign engine i'd go one better and do the damn 4.6L mod swap. At this point i'm open to anything (that isn't a Chevy... come on now...), and well... Ford does what i want better than Mopar does. I dont need 350cid.
That G3 hemi howl does grow on ya though... Now... if they made a 4.7L or 5L hemi, with an aluminum block...
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Re: Is the 360 an inherently inefficient engine?
[Re: dodgedon]
#1622047
05/20/14 05:38 AM
05/20/14 05:38 AM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
Pale_Roader
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Quote:
The 360's in trucks that i have seen always had lower gears in them. 3/4 and 1 tons had 4:10 and lower gears. If it was a half ton it had 3:91... The 318's I have seen in 1/2 tons in the 70/80's had 3:23 gears and in the 90's and up had 3:55's Those low gears realy hurt MPG.
Yup... 1/2 to 3/4 point in extra gearing is going to do far more damage to MPG than 40cid.
Reading ALL the replies though... it seems pretty clear now. Unless a cherry 5.9L falls onto my lap for free before i nab the 5.2 at the yard, i'll go with the 318.
Reading all this i am reminded ov a friend's 72 Dart i used to work on. It had come to him with a badly modded (original) 318. Unported 318 heads, stock CR, an ancient single plane, big Holley, awful and bashed headers, way choked-up exhaust, the WRONG cam... etc. That car flat-out flew. It was 300-400lbs heavier than my car will be, automatic (727 no doubt...), its only saving grace was 3.91 gears.
That was almost fast enough. If what i've planned isn't considerably quicker (even with the crappy gearing i'm gonna use) i'd be shocked. Totally forgot about that car...
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Re: Is the 360 an inherently inefficient engine?
[Re: Pale_Roader]
#1622048
05/20/14 07:37 AM
05/20/14 07:37 AM
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Joined: Jan 2003
Posts: 8,936
Holly/MI
Dean_Kuzluzski
master
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master
Joined: Jan 2003
Posts: 8,936
Holly/MI
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Do a web search on KB167 and the KB399's. Some pretty impressive et's by A-bodies that are around 3000#.
Even with the "junk" J/X/O heads that got superstock prep'd Dusters well into the 11's.
It's all in the combo. The factory compression and cam for the 360 was a total turd combo. 360's run great built right.
crap combo = crap performance.
R.I.P.- Gary "Coop" Davis 02/09/68-05/13/04
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Re: Is the 360 an inherently inefficient engine?
[Re: Pale_Roader]
#1622050
05/20/14 12:57 PM
05/20/14 12:57 PM
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Joined: Jan 2006
Posts: 8,162
USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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Quote:
Here are my stipulations for this project:
1 - MUST be a V8.
2 - BEST gas mileage possible (and dont lecture me on driving or hypermiling) By this i mean hammering on a 4.6L mod will still get me past far more gas stations than hammering on a 440 Mopar in the same car with the same gearing.
3 - Must make decent power. Now 'decent' for me, at this stage anyways means 300HP net or close to. That'll go fast enough for my 3000lb daily driver.
For what it is worth, here are some computer engine modelling runs using the Performance Trends EA3.2 program:
Baseline is factory 1995 Magnum 5.2 with static compression ratio of 9.1 making
296 FT-Lbs of Torque at 3400 RPM and
228 net SAE HP at 4400 RPM
Bore 20 thousands over
add MPI single plane manifold
add 4 into 1 tube headers
42 inch long primaries and 1.5 inch internal diameter,
plus low restriction exhaust
stock camshaft
Stock SMPI
Result
300 SAE net HP at 5200 RPM
332 FT-Lbs Torque at 4000 RPM
A new aggressive camshaft
or inexpensive regrind
would give more
but would probably hurt daily driving MPG
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Re: Is the 360 an inherently inefficient engine?
[Re: MoparforLife]
#1622052
05/20/14 01:37 PM
05/20/14 01:37 PM
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Joined: Apr 2005
Posts: 15,134
Kelowna, B.C. Canada
DPelletier
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 15,134
Kelowna, B.C. Canada
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1) the answer to your question is no. ....the myth about inefficiency as it relates to the 360 engine design is because a) people were comparing the larger displacement and lower output of the 360 to the 340 and b) the 360 in most trucks were is a D/W200 with lower gears than a D100 318 and mileage was far different for the obvious reasons. 2) Sheldon's right, the 360 doesn't get the respect it deserves....it was a good performer in the mid to late '70's considering what else was out there. 3) minor differences aside, the basic LA architecture remains the same across the board...given the same cam, heads and compression, I'd expect them to make roughly the same hp/cu in.  Dave
1970 Super Bee 440 Six Pack
1974 'Cuda
2008 Ram 3500 Diesel
2006 Ram 3500 Diesel
2004.5 Ram 2500 Diesel
2003 Ram 3500 Diesel
2006 Durango Limited
[url] http://1970superbee.piczo.com [/url]
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Re: Is the 360 an inherently inefficient engine?
[Re: GY3]
#1622053
05/20/14 01:58 PM
05/20/14 01:58 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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No way no how is a 360 57# heavier than a 318. 5# maybe. The crank is a tad heavier, the pistons a tad lighter I have two blocks here that are both 165# on my scale bare. Nothing else is really different, both are 97 magnums.
The 318 mag pistons were .037 ish down the hole and .049 thick graphite like factory head gaskets. The 360 about the same but a big dish in the piston to make things wose. The 318 mag has a higher compression ratio AND a better cam (more lift less duration). I have driven a ton of the 5.2 and 5.9 magnum trucks new when I worked at the dealer and some 5.2s were fast and some 5.9s were weak, one motor to the next could have very different performance, you could never be sure witch one you had till you popped the hood.
None of the 5.9 trucks I have owned seem to be significantly worse MPG (just a tiny bit)than the 5.2 trucks, they were all crappy MPG except the one 318 I zero decked the block and ran .039 head gaskets, it made a huge differance, way more than I predicted or even dreamed of. I bet a 5.9 would respond the same way especially with a 5.2 cam.
Another problem is the 518 tranny, it is big heavy and sucks power out of them, one time I swapped a 904 into a dakota and the power difference was huge. An a-500 would be the real ticket behind the 5.9, Lower gears, lower weight, lower drag...
It is all about the complete package. The early 318 TBI motors had a great package, a-500 higher compression, small (tiny) cam, and the TBI does a better job with the fuel than the MPI because it has more time to va-poo-rize. Can't compare it to a 360 without looking at the whole package.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Is the 360 an inherently inefficient engine?
[Re: HotRodDave]
#1622054
05/20/14 08:33 PM
05/20/14 08:33 PM
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Joined: Jan 2011
Posts: 15,831
Central Florida
larrymopar360
Stud Muffin
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Stud Muffin
Joined: Jan 2011
Posts: 15,831
Central Florida
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I've had several 318's and 360's. Always impressed with the power of the 360's I've had. Actually very impressed. Mileage worse than a 318? Yes, but over 40 more cubic inches. I've had two Mopar Performance Magnum 360's that were very fast torquey engines, and with 2.94 gears in a 3800 pound car the mileage was VERY reasonable. My Aspen has the factory E58. I am very happy with the performance and love driving it. Mileage is low with the thermoquad and it's hard to keep my foot out of it, but again, it's over 40 cubes bigger than a 318.
The ONLY con I would put on the 360 versus the 318 is the external balance vs. internal. The perfect smallblock in my mind is a built, internally balanced 360.
Facts are stubborn things.
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Re: Is the 360 an inherently inefficient engine?
[Re: 360view]
#1622055
05/20/14 09:36 PM
05/20/14 09:36 PM
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Joined: Jan 2006
Posts: 8,162
USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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Re: Is the 360 an inherently inefficient engine?
[Re: larrymopar360]
#1622056
05/20/14 09:51 PM
05/20/14 09:51 PM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
Pale_Roader
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Well i'm sold. For MY needs right at this moment, the 318 Magnum will do fine. Again, WHEN i install it i'll be using an RPM Air-Gap, small Holley, Doug's headers, true mandrel 2.5" exhaust w X and real mufflers, and it will have no accessories to rob power, plus a 4-speed. The only crappy point will be 2.76 gears, but thats a necessary evil until i can afford a 5 or 6-speed. Its not a drag car anyways... only needs to be fast from a 20-30MPH roll on. Down the road i'll be getting some Edelbrock Magnum heads and a better (modern) cam. When that happens, maybe i'll get lucky and find the pistons only .020-.030 down the hole and can actually scavenge some quench with steel head gaskets. The basic bolt on Edelbrock head swap should make an easy 400HP on a 318 (it made 450 on the 360). That'd be cookin'...
Fort what its worth, i've always thought the 360 in all its forms was a great engine. I drove a car with a first-year 71 360 (from a Fury) that someone had swapped a 70 intake/carb and exhaust manifolds on. That engine felt every bit as fast, if not faster than any 68-70 340 i've driven, even my really nice A66. For what it was, my 100% bone-stock 78 Volare with its 360 was not a slow car, and it had even worse than 2.76 gears.
Right now i just like the idea ov small engines that make big HP higher up the tach. Provided it doesn't have a stooopid cam in it, you can drive a high-RPM engine normally in the lower ranges to get around and still make decent MPG... well, with a stick anyways. Hard or impossible to do that with a big engine. Again, it helps to have a light car.
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Re: Is the 360 an inherently inefficient engine?
[Re: Pale_Roader]
#1622058
05/20/14 10:46 PM
05/20/14 10:46 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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Same heads, same cam, same intake, same exhaust, the 318 will make the same HP as the 360, just at a higher RPM.
In other words, more head, more cam, and the 360 will blow away the 318.
My 5.9 had eddy heads, is making around 400 crank HP. and still gets 16 mpg overall... With a heavy foot.
The mustang 4.6 has much better heads than the 318 or 360, thus why it makes more power and gets better mileage than any 5.2 or 5.9 with stock heads.
**Photobucket sucks**
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Put on a set of Hughes stage 1 heads and Hughes cam and ran consistent low 11.40's, dipping into the the 11.30's. Still no aftermarket balance. Ran that motor for several years and then sold the car.
good luck OP! 