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Re: 360 Magnum vs 383... What would make more power?
[Re: Dean_Kuzluzski]
#1393763
03/02/13 09:15 PM
03/02/13 09:15 PM
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Posts: 4,862
the frozen wastes...
Pale_Roader
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Quote:
Interesting thread topic................the 360 has a longer stroke and shorter rod.............383 has longer rod, shorter stroke. Lets overlook the 23 more cubes to the 383 for moment...........
typically that 383 will get you better efficiency/mpg at a slightly higher rpm. The 360 will give you more torque off idle/low rpm with the longer stroke and more agressive rod/stroke ratio...............
where is this going???? With the 2.94 gearing and LOTS of mileage..........I'd be looking to do the 360 UNLESS it's all interstate travel.
I, personally, wouldn't want to feed a thirsty V8 on a high mileage daily basis. If I had to, I'd build it for max mpg and big torque down low where it's going to spend all of its time.
Heh... EXACTLY. Thats why i want an efficient V8 for this project. Its funny i've come a complete 180 in the last few years, but now i wish Mopar had made an even smaller 3rd gen hemi... 300cid or smaller. If i had to go through all the trouble and BS ov installing a new EFI engine in this car it'd probably be the 4.6L or 5L Ford mod... simply because it makes the same amount ov power from way less cubes.
If i were to build a specific engine for this car down the road it might even be smaller than the 360... maybe a 318 Magnum... or even a 340 Magnum. Again, i have the bonus ov having a light car... that will just get lighter and lighter as i go.
Quote:
I put LOTS of hours into porting a set of 516's for a .060 over 383 in my 69 RR. Did the MP porting templates. Went 1.74 exhaust valve too. Just gasket matching, opening up the bowls, working the valve guide boss can all run into lots of hours. And I think with a mild cam it would raise the efficiency of the motor such that it isn't a detriment to mpg. My RR got 14 mpg hwy to Indy from MI with a 750 AFB, single-plane, 484MP cam and 3.91 gears. Not a gasmizer deal at all but it did like to run at 3000-3400. I gained 2-3 mph thru the traps too! 
I dont mind porting... kinda find it fun actually. Time well spent.
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Re: 360 Magnum vs 383... What would make more power?
[Re: HYPER8oSoNic]
#1393764
03/02/13 09:18 PM
03/02/13 09:18 PM
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Posts: 4,862
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Quote:
Quote:
Interesting thread topic................the 360 has a longer stroke and shorter rod.............383 has longer rod, shorter stroke. Lets overlook the 23 more cubes to the 383 for moment...........
typically that 383 will get you better efficiency/mpg at a slightly higher rpm. The 360 will give you more torque off idle/low rpm with the longer stroke and more agressive rod/stroke ratio...............
where is this going???? With the 2.94 gearing and LOTS of mileage..........I'd be looking to do the 360 UNLESS it's all interstate travel.
I, personally, wouldn't want to feed a thirsty V8 on a high mileage daily basis. If I had to, I'd build it for max mpg and big torque down low where it's going to spend all of its time.
I put LOTS of hours into porting a set of 516's for a .060 over 383 in my 69 RR. Did the MP porting templates. Went 1.74 exhaust valve too. Just gasket matching, opening up the bowls, working the valve guide boss can all run into lots of hours. And I think with a mild cam it would raise the efficiency of the motor such that it isn't a detriment to mpg. My RR got 14 mpg hwy to Indy from MI with a 750 AFB, single-plane, 484MP cam and 3.91 gears. Not a gasmizer deal at all but it did like to run at 3000-3400. I gained 2-3 mph thru the traps too!
 A 383 can be built to be efficient as can a 360. the question is simple how hard are you willing to spin the motor at cruising speed. Since it take extra fuel to keep a short stroke motor accelerating (under load) vs a longer stroke motor, it would be much more feasible to build a motor with more low end torque in it. Since you do have 95% percent of the parts for the 383, build it. The Whiplash cam WILL raise the cylinder pressure (increase static-EFFECTIVE compression) by allowing cam timing events to happen sooner in the combustion process. The two
things you must do to "maximize" your power/efficiency/mileage goals is to degree the cam CAREFULLY!! Cam timing is critical and I'd make sure the damper is indexed properly for ignition timing/tuning purposes. Old dampers could have their ignition mark OFF by several degrees! All the above mods/checks can net you a
smoother, more efficient motor. The K.I.S.S. (Keep It Simple Stupid) principle always works! 
Between the Whiplash cam and the shaved heads (later on) i should be doing okay dynamic compression-wise. Everything but quench... which would really be nice for the end-goal here.
I'll have to check that balancer.
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Re: 360 Magnum vs 383... What would make more power?
[Re: Pale_Roader]
#1393765
03/02/13 09:28 PM
03/02/13 09:28 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
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The whip lash cam you are set on is gonna waste a lot of fuel, too much overlap.
As for the too big of an engine complaint, just gear it higher it has the same effect.
A long stroke does not give any more TQ than a big bore engine of the same displacement, this has been proven a myth many times. It can mean you are getting a shrouded valve by the bore so breathing is limited making the engine a lower RPM type engine but if valve shrouding is not an issue then the bigger stroke does not make a difference.
A longer stroke will have more leverage on the crank but less surface area on the top of the piston for the pressure to push on, those two forces seem to balance each other out both theoretically in the real world. The real difference in big bore VS long stroke is valve shrouding.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: 360 Magnum vs 383... What would make more power?
[Re: HotRodDave]
#1393767
03/03/13 09:14 AM
03/03/13 09:14 AM
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Posts: 4,862
the frozen wastes...
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Quote:
The whip lash cam you are set on is gonna waste a lot of fuel, too much overlap.
As for the too big of an engine complaint, just gear it higher it has the same effect.
A long stroke does not give any more TQ than a big bore engine of the same displacement, this has been proven a myth many times. It can mean you are getting a shrouded valve by the bore so breathing is limited making the engine a lower RPM type engine but if valve shrouding is not an issue then the bigger stroke does not make a difference.
A longer stroke will have more leverage on the crank but less surface area on the top of the piston for the pressure to push on, those two forces seem to balance each other out both theoretically in the real world. The real difference in big bore VS long stroke is valve shrouding.
Yeah... i do realize the cam choice hurts my overall plan a bit... but its the one guilty pleasure i'm allowing myself. At least its a modern Mopar-lobe cam and has some cylinder-pressure building capability. Plus... it sure sounds mean.
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Re: 360 Magnum vs 383... What would make more power?
[Re: HYPER8oSoNic]
#1393768
03/03/13 09:17 AM
03/03/13 09:17 AM
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Quote:
Balancing the motor adds some "free" hp, may extend you rpm range a bit (valvetrain pending) and lengthen the life of the motor. Something to  about.
I'm a BIG fan ov the full balance treatment. The factory balance on Mopar stuff has always been one ov my chief criticisms ov the Mopar engines. Unfortunately... that quite literally jacks up my budget by about 10 times. No money for it.
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Re: 360 Magnum vs 383... What would make more power?
[Re: Pale_Roader]
#1393770
03/03/13 02:57 PM
03/03/13 02:57 PM
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Joined: Jan 2003
Posts: 5,186
Wherever I am.
Junky
master
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Joined: Jan 2003
Posts: 5,186
Wherever I am.
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Quote:
Quote:
The whip lash cam you are set on is gonna waste a lot of fuel, too much overlap.
As for the too big of an engine complaint, just gear it higher it has the same effect.
A long stroke does not give any more TQ than a big bore engine of the same displacement, this has been proven a myth many times. It can mean you are getting a shrouded valve by the bore so breathing is limited making the engine a lower RPM type engine but if valve shrouding is not an issue then the bigger stroke does not make a difference.
A longer stroke will have more leverage on the crank but less surface area on the top of the piston for the pressure to push on, those two forces seem to balance each other out both theoretically in the real world. The real difference in big bore VS long stroke is valve shrouding.
Yeah... i do realize the cam choice hurts my overall plan a bit... but its the one guilty pleasure i'm allowing myself. At least its a modern Mopar-lobe cam and has some cylinder-pressure building capability. Plus... it sure sounds mean.
I'm running the Whiplash cam in my 383. On the interstate cruising at 3,200 to 3,400 RPM with 3.73 gears and 28" tall tires, I get 12 mpg. Good enough for me. I think the Whiplash cam is a really good choice for a hot "street cam" with compression under 10 to 1 especially for an engine like mine that makes 9 to 1 at best.
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Re: 360 Magnum vs 383... What would make more power?
[Re: patrick]
#1393772
03/05/13 04:12 AM
03/05/13 04:12 AM
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Posts: 4,862
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Quote:
Quote:
Heh... EXACTLY. Thats why i want an efficient V8 for this project. Its funny i've come a complete 180 in the last few years, but now i wish Mopar had made an even smaller 3rd gen hemi... 300cid or smaller. If i had to go through all the trouble and BS ov installing a new EFI engine in this car it'd probably be the 4.6L or 5L Ford mod... simply because it makes the same amount ov power from way less cubes.
well....the hemi in my charger is only 2.85L.....when it's working in MDS mode.....
Well if you like it thats great. But personally i think that is just backwards thinking on Mopar's part. They should have just designed a more efficient V8. I dont want a part time V8, i want an all-time V8. The MDS tech just seems hokey to me and i'll never ever warm up to it. But again... thats just my (unpopular) opinion.
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Re: 360 Magnum vs 383... What would make more power?
[Re: Junky]
#1393773
03/05/13 04:17 AM
03/05/13 04:17 AM
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Joined: Jan 2005
Posts: 4,862
the frozen wastes...
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Quote:
Quote:
Quote:
The whip lash cam you are set on is gonna waste a lot of fuel, too much overlap.
As for the too big of an engine complaint, just gear it higher it has the same effect.
A long stroke does not give any more TQ than a big bore engine of the same displacement, this has been proven a myth many times. It can mean you are getting a shrouded valve by the bore so breathing is limited making the engine a lower RPM type engine but if valve shrouding is not an issue then the bigger stroke does not make a difference.
A longer stroke will have more leverage on the crank but less surface area on the top of the piston for the pressure to push on, those two forces seem to balance each other out both theoretically in the real world. The real difference in big bore VS long stroke is valve shrouding.
Yeah... i do realize the cam choice hurts my overall plan a bit... but its the one guilty pleasure i'm allowing myself. At least its a modern Mopar-lobe cam and has some cylinder-pressure building capability. Plus... it sure sounds mean.
I'm running the Whiplash cam in my 383. On the interstate cruising at 3,200 to 3,400 RPM with 3.73 gears and 28" tall tires, I get 12 mpg. Good enough for me. I think the Whiplash cam is a really good choice for a hot "street cam" with compression under 10 to 1 especially for an engine like mine that makes 9 to 1 at best.
Heh... well if my 383 gets 12mpg it'll be coming back out as fast as it went in. I've had a crappy-mileage Mopar... and i dont care how fun or how fast it was, it was a useless car to me. Utterly. My Challenger wont have 3.73 gearing though, or anything even close to that... so i'm hoping i can squeeze closer to 20 out ov it if i drive like a normal human being.
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Re: 360 Magnum vs 383... What would make more power?
[Re: dulcich]
#1393774
03/05/13 04:20 AM
03/05/13 04:20 AM
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Joined: Jan 2005
Posts: 4,862
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Quote:
Pale Guy,
Forget about everything you have read on this thread, and all the hypothetical theory BS. Put in the 383, add the OD as you can (833 will work good), and you'll have one great running Challenger without breaking the bank.
-dulcich
Hey! Wow, i get Ehrenberg in my other thread, and you in this one.
Curious. Care to share WHY you dont like the Magnum idea? simplicity? money? or just the fact i already have all the 383 stuff handy? You dont think the Magnum's are better, more efficient technology? My 383's heads were designed in the 50's... thats gotta count for something...
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Re: 360 Magnum vs 383... What would make more power?
[Re: MagnumGT]
#1393777
03/06/13 06:02 AM
03/06/13 06:02 AM
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Joined: Jan 2005
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Quote:
Well you have lots of technical info, it seems you have a philosophical question... a poker game, do I keep what I got, raise the stakes, or fold. After the last election I would absolutely put what I got together and ride. For every one of you guys with questions... there's two out there wishing they had your problems! The only way to get 20 MPG to me would be dropping in the entire Mag drivetrain out of a Dakota. If all your stuff was small block I would say the same thing... selling/trading/buying/rebuilding is all time consuming but most of all ...INEFFICIENT. I could make a flathead V8 efficient by drowning it in all new-tech parts and a 6-speed etc. Get out there and drive before we can't anymore.  
Oh i've already long decided what i'm going to do. I just wanna DRIVE this thing! So it would be mad to spend another year selling all my big block stuff, buying all the small block stuff, etc. Plus... i know big blocks. Gonna put together my nice lil 383 combo i've detailed above, with my 1:1 4-speed and some 2.76 gears and have some fun. Who knows... i might even be able to get to work again... WHILE i'm driving that and enjoying that i'll definitely be keeping the eyes peeled for a nice 360 Magnum, and all the swap stuff. I'll probably install that when i have a 5 or 6-speed lined up, and kill all the birds with one stone.
I'm still curious about Dulcich's thoughts on my above post...
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Re: 360 Magnum vs 383... What would make more power?
[Re: Pale_Roader]
#1393778
03/09/13 05:38 PM
03/09/13 05:38 PM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
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Indiana
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Quote:
I'm still curious about Dulcich's thoughts on my above post...
That response might be relating to 'there's an awful lot of theory here, and proof is in the pudding, so save time and use the parts you already have'.
Or it might be 'I know more than everyone else and can spare only enough time to give you the correct answer, but I'm too busy to give the explanation'.
Not speaking of Dulcich, but merely about short responses that come in late in a long discussion like this.
I'm like you, Pale, I like healthy used low-buck engines. I'd use the 383 as that's the stuff you have on-hand. I would skip that Whiplash and use a Lunati 60302 (or 1 size smaller). Do a compression check and pick the cam based on cyl pressure. would be a nice engine to put that new StreetDemon T-quad-type carb on too.
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driver doorpanel, 65 Sport Fury, prefer black, needs to be 7-8 on 10 scale, might buy set
16" x 6" Dodge truck wheel(s), from early 70s?, takes 9" dogdish - need for a research job so cheaper is better.
69-73 C-body caliper brackets and/or splashields
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Re: 360 Magnum vs 383... What would make more power?
[Re: dulcich]
#1393781
03/09/13 10:23 PM
03/09/13 10:23 PM
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Quote:
You pretty much hit it in your first response. You have the stuff, so that is a good reason to use it. If you have a 383 and think that going through a bunch of extra effort to swap to a 360 Mag will make for a much more efficient package, you'll end up not getting much reward for the effort. Really, fuel efficiency has never been a strong point with any 360 I've ever seen.
I'm not going to argue with you, because mainly i cant... i have zero experience with 360's, aside from one bone stock Volare that i never turned a wrench on (that actually got really good mileage... but had ridiculously long rear gears). But i just cant see why a 360 should be so bad on gas, especially a Magnum. I've heard that from so many people, many good engine guys even... but it is hard to make sense ov... on paper it looks like it should be better than a 340/350/351... Personally i think its just the vehicles they came in (mid-late 70's smog-boats, anything in the 80's, and very heavy 90's trucks/vans), and the type ov driving seen in those vehicles. Thats my theory anyways.
Or maybe the Magnum 318 is a better option. I'd hate to give up even more speed... but again this will be a light car... maybe i can get away with it.
And yeah... i understand the whole 'buy a $20000 Honda to save 10mpg, or keep the 15mpg old car and spend that $20000 on gas' catch-22 argument. In MY experience... having always been poor i've always found the better mileage car simply gets used a lot more. Saving the money spent on efficiency upgrades to spend on gas instead never EVER works for me. That money, if not spent on a better car/engine... just gets spent on other stuff instead and i'm STILL stuck not going anywhere because my car gets crappy mpg. I NEVER have money kicking around/saved.
That said i AM using the 383 right now... i'd be an idiot not to. I'm just thinking ahead on the SB stuff.
Quote:
With your goals (20mpg?), I probably wouldn't go with that big overlap WL cam either.
I know that one will hurt... but like i said, its my ONE guilty pleasure i'll allow myself. Never had a car with a big cam before.
Quote:
The 383 is actually a very good all around street engine. For MPG and good horsepower, I would build it with the CC heads, a short cam with wide lsa and big exhaust split (stock Magnum cam maybe; 1.6rr would help on the power side), work the heads for flow and run tight quench. I always like your posts, PR, you seem to have a good perspective. Give some more details about your combo.
-dulcich
Heh... thanks. I love the 383, always have. So much more than the 440. I like everything about the lowdeck. My original plan was to build a nasty 400 stock-stroke lowdeck and scream it to the moon (talk about your awesome MPG...). Had the B1's, tunnel ram, 2 230 blocks to choose from, etc. Never got off the ground because i couldn't get past the $1000 buy-in for the rocker system. I still have a lot ov good parts for lowdecks.
Details huh? well, how about my proposed combo...
-67 383 2-bbl engine (low comp, i probably dont wanna know... JohnRR depresses me every time he brings it up) unrebuilt and staying that way
-Holley SD intake, basic mild plenum mods that worked VERY well on my 440, no heat crossover
-Many different spacers to play with
-Holley 800DP or Street Avenger 670 to choose from. K&N stub stack
-alum water pump and housing, single groove stock pulleys (car has no accessories)
-MSD Pro-Billet dist. Will be getting the MSD box too.
-Chrome oil pan (deeper, stiffer than stock, gonna paint it engine color, i dont like chrome)
-Alum valve covers
-Mini starter (Dakota)
-Hedman shorty headers with modified collectors (because the stock ones suck)
OR
-Long tubes (whatever i can afford)
-3" mandrel X-pipe duals w Spintechs and T/A style exit
Not yet acquired...
-Whiplash cam (like the sound, the modern Chrysler lobes, seems to make good power, REALLY like the cylinder pressure building effect)
-Machining on another pair o' 516 heads i have. Was gonna install some new Ferrea 1.81's (that i have already), port 'em as far as i dare, cut the guides, shave 'em as far as i dare.
I may or may not do the head swap before dumping the plant in the car. If the guides NEED to be cut for a .518" cam (they dont for the Mopar .509"...???) then i guess i'll have to, but i'd really like to avoid it for now. That machining is gonna add up i'm sure...
There is no money for a rebuild, so no quench unfortunately. I looked far and wide for a 68-9 383 Magnum runner, hoping i could get closer to quench and better compression... but never found one. The 67 came out ov a very nice 300, and i knew the owner.
Rest ov the car:
-Lakewood scattershield (have block saver too)
-McLeod PP (have to buy a different clutch disc though)
-Hurst Super Shifter 3 with Pistol grip
-833 out ov 70 340 Cuda
-8 3/4" rear (not in car, have yet to put it together or find a pumpkin... the sure grip i had turned out to be junk)
-Might get tricky and mickey-mouse an aluminum driveshaft from something at the wrecker (dont have a shaft yet)
-Aluminum rad (junkyard)
-Electric fuel pump
The car is a 70 Challenger 6 cyl/3speed car. The final first-phase curb weight with the big block (and now that i just sold my FG hood, dammit) should be around 3150lbs. And yes... it WILL be that light. I'm a weight-reduction master (and dont even own a hole-saw).
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Re: 360 Magnum vs 383... What would make more power?
[Re: Pale_Roader]
#1393782
03/10/13 08:04 AM
03/10/13 08:04 AM
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Joined: Jun 2008
Posts: 10,847
Oakdale CT
gdonovan
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Quote:
But i just cant see why a 360 should be so bad on gas, especially a Magnum. I've heard that from so many people, many good engine guys even...
I have a 94 magnum 5.9 in my Duster with a 42RH trans & 3.55's and it gets well over 20 mpg on the highway.
Has Enginequest "iron ram" heads, LA windage tray, CompCams .510 magnum roller, Edelbrock RPM dual plane, Carter AFB and stock manifolds.
Car just goes to beat the band and on the highway turns 1800-1900 rpm while doing 75-80 mph. Overdrive and lockup rules!
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