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360 Magnum vs 383... What would make more power? #1393683
02/26/13 08:18 AM
02/26/13 08:18 AM
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the frozen wastes...
Pale_Roader Offline OP
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All things (possible) being equal anyways...

Lets say 3100lb car, 4 speed, longtube headers and a VERY good exhaust system.

My original plan was a 67 383-2bbl longblock (not rebuilt), so lower "9.2:1" CR, Holley Street Dominator, Holly 750-800DP, MSD dist, no accessories, etc. Whiplash cam.

The option now is a mid-90's (or best year) 5.9L Magnum (unrebuilt), RPM Air-Gap, proper-sized Holley DP, elect. ign, no accessories, Whiplash magnum cam (to keep the comparison equal-ish).

Will the roller cam/better rockers and more modern heads make up for the 23cid and bigger everything? I'm sure it will kill the 383 in mileage. How about power?

I'm just talking about power here... bench racing... i realize the car would be generally faster (straight, top end, cornering) with the Magnum due to the weight difference.

Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393684
02/26/13 09:11 AM
02/26/13 09:11 AM
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Sault Ste. Marie, Ontario, Can...
moparmike1 Offline
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I was planning a 383 for my long-term project Challenger but with the 360 magnum, 400 hp is an easy goal to reach so basically both engines would be on par. I'm going with either a 360 magnum or a 408 with the expectation the car will handle better as opposed to having a 383.

Mike.

Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393685
02/26/13 09:14 AM
02/26/13 09:14 AM
Joined: Oct 2003
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Marysville, O-H-I-O
70Cuda383 Offline
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the bigger cubic inches will make more power.


but, how much more hp? I've seen some 360s with some very impressive heads that can make big hp numbers.

and at how much of a weight penalty? the big block will be heavier than the 360, so even if it makes more Hp, may not actually be faster.


but, generally, dollar for dollar, the bigger motor will win


**Photobucket sucks**
Re: 360 Magnum vs 383... What would make more power? [Re: 70Cuda383] #1393686
02/26/13 10:10 AM
02/26/13 10:10 AM
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the frozen wastes...
Pale_Roader Offline OP
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Quote:

the bigger cubic inches will make more power.


but, how much more hp? I've seen some 360s with some very impressive heads that can make big hp numbers.

and at how much of a weight penalty? the big block will be heavier than the 360, so even if it makes more Hp, may not actually be faster.


but, generally, dollar for dollar, the bigger motor will win




You can put B1's on a 383, yet you can put some serious head on a Magnum too...

I'm talking at stockish levels here though. Basic mild bolt-ons at most... Whiplash cam, RPM/SD intake, optimal carb, headers, exhaust, hot ignition... etc. STOCK compression on either engine though.

My underlying point was is the newer technology (roller and modern heads) enough to offset the 23 cubes?

As a part two... lets go as far as some entry level porting on either head. How about then?

Re: 360 Magnum vs 383... What would make more power? [Re: moparmike1] #1393687
02/26/13 10:12 AM
02/26/13 10:12 AM
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Posts: 4,862
the frozen wastes...
Pale_Roader Offline OP
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the frozen wastes...
Quote:

I was planning a 383 for my long-term project Challenger but with the 360 magnum, 400 hp is an easy goal to reach so basically both engines would be on par. I'm going with either a 360 magnum or a 408 with the expectation the car will handle better as opposed to having a 383.

Mike.




Yeah... i LOVE the idea ov a stock-stroke low-deck big block... and i've been collecting parts for mine for years... but all this Magnum talk and the awesome $1.30 price ov gas has me really thinking ov selling my 383 and pile o parts... I've already sold my B1BS's...

Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393688
02/26/13 10:16 AM
02/26/13 10:16 AM
Joined: Jan 2013
Posts: 167
maryland
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74yellowduster Offline
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maryland
Quote:

Quote:

the bigger cubic inches will make more power.


but, how much more hp? I've seen some 360s with some very impressive heads that can make big hp numbers.

and at how much of a weight penalty? the big block will be heavier than the 360, so even if it makes more Hp, may not actually be faster.


but, generally, dollar for dollar, the bigger motor will win




You can put B1's on a 383, yet you can put some serious head on a Magnum too...

I'm talking at stockish levels here though. Basic mild bolt-ons at most... Whiplash cam, RPM/SD intake, optimal carb, headers, exhaust, hot ignition... etc. STOCK compression on either engine though.

My underlying point was is the newer technology (roller and modern heads) enough to offset the 23 cubes?

As a part two... lets go as far as some entry level porting on either head. How about then?




newer isnt neccesarily better... actually some of those LA magnum heads like to crack exhaust valve seats in those "modern" heads.

a steel crank 383 at 13:1 on E85 with eddy heads, E85 quickfuel carb and a .528 mopar cam would seriously blow that 360 out of the water.

you would need to do some serious work to the magnum to get at the same level, costing way more and even then it would not be as long-lived.

Re: 360 Magnum vs 383... What would make more power? [Re: 74yellowduster] #1393689
02/26/13 10:24 AM
02/26/13 10:24 AM
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Maud,Tx
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maud Offline
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Maud,Tx
I'd go with the big block. Even if they were equal at the track. I like the big block's water pump and timing cover setup, along with the oil pump, distributor drive shaft, not to mention you can actually see the distributor without laying across the motor.

Re: 360 Magnum vs 383... What would make more power? [Re: 74yellowduster] #1393690
02/26/13 10:37 AM
02/26/13 10:37 AM
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the frozen wastes...
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Quote:


newer isnt neccesarily better... actually some of those LA magnum heads like to crack exhaust valve seats in those "modern" heads.

a steel crank 383 at 13:1 on E85 with eddy heads, E85 quickfuel carb and a .528 mopar cam would seriously blow that 360 out of the water.

you would need to do some serious work to the magnum to get at the same level, costing way more and even then it would not be as long-lived.




13:1...??? Aluminum heads...??? Dude... you just built me a $5000 engine. A running 383 or 360 Magnum (that doesn't need a rebuild) will run me less than $500. I can sell my 383 to buy a 360 Mag, so essentially free for me. NOBODY is building an engine here.

STOCK 383 + bolt ons vs STOCK 360Mag + (same) bolt ons.

Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393691
02/26/13 11:18 AM
02/26/13 11:18 AM
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maryland
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74yellowduster Offline
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ok for cheap then, just get the solid .528 cam for the 383 & e85 quickfuel carb have the heads milled to get you to 12:1 or so (iron heads, alum could go to 13:1) run a 180 deg thermostat

you will probably want to run an elec fuel pump with return style regulator/bypass if you go E85

on straight pump gas, ok yeah the 360magnum might have an edge. just watch when you buy one though make sure the exhaust valve seats are not all cracked up. if it came out of a pickup, rode real hard they probably are.

Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393692
02/26/13 11:21 AM
02/26/13 11:21 AM
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connecticut
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connecticut
keep the trans in mind...all things equal unless this is a hypothetical situation if you have a big block and are thinking of changing to a small block...everythings different...that can get expensive. as for power id go with the 383 they make gobs of torque, rev to the moon, you could find a set of closed chamber heads put bigger valves in them some mild porting and make a low budget screamer. I had a 440 with 67 lopo closed chamber with a valve job and bigger valves, stock short block a used fireball cam and iron sixpack and it put 400hp and 550 ft lbs to the pavement with a real conservative tune had 2500 into the whole deal with the sixpack 1200 into the engine and most of that was the headwork


"Are you gonna bark all day lil doggy? Or are you gonna bite?"


05 ram 2500 ctd
74 gremlin x 360
65 mustang 347
70 coronet R/T 440
03 Mach 1
Re: 360 Magnum vs 383... What would make more power? [Re: 74yellowduster] #1393693
02/26/13 12:10 PM
02/26/13 12:10 PM
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U.S.S.A.
JohnRR Offline
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Quote:

ok for cheap then, just get the solid .528 cam for the 383 & e85 quickfuel carb have the heads milled to get you to 12:1 or so (iron heads, alum could go to 13:1) run a 180 deg thermostat






Do you have any idea hom much would have to come off a set of heads to get his low compression 383 , he's lucky if it's 8:1 on its RATED 9.2 compression.

I just ran some numbers , the pistons in his engine are probably .080 in the hole , if this is the case he would have to have a head with a 46cc chamber to get 12.0 in a 383.

If his heads are 84cc he would have to cut .190 off them to get the chamber down to 46 cc.

It's a nice thought but not something doable with his low budget build with parts he has laying around .

Re: 360 Magnum vs 383... What would make more power? [Re: JohnRR] #1393694
02/26/13 12:44 PM
02/26/13 12:44 PM
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God's Country Maryland
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With the bore of a 383 (4.25) you can go with a lot bigger valves than you'd ever get into a 360's bore (4.00).


I love the smell of Deer guts in the morning, it smells like... VICTORY!
Re: 360 Magnum vs 383... What would make more power? [Re: JohnRR] #1393695
02/26/13 12:50 PM
02/26/13 12:50 PM
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maryland
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74yellowduster Offline
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Quote:

Quote:

ok for cheap then, just get the solid .528 cam for the 383 & e85 quickfuel carb have the heads milled to get you to 12:1 or so (iron heads, alum could go to 13:1) run a 180 deg thermostat






Do you have any idea hom much would have to come off a set of heads to get his low compression 383 , he's lucky if it's 8:1 on its RATED 9.2 compression.

I just ran some numbers , the pistons in his engine are probably .080 in the hole , if this is the case he would have to have a head with a 46cc chamber to get 12.0 in a 383.

If his heads are 84cc he would have to cut .190 off them to get the chamber down to 46 cc.

It's a nice thought but not something doable with his low budget build with parts he has laying around .




there were different 383's some 10:1 some 9.5:1 some 8.5:1 etc.

Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393696
02/26/13 01:02 PM
02/26/13 01:02 PM
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Morristown Tn.
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71birdJ68 Offline
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I don't know about the Magnums, but I would wind a 68 C body with a 383 2b to 65 mph in first gear, on a regular bases, they are almost indestructible.

Re: 360 Magnum vs 383... What would make more power? [Re: 74yellowduster] #1393697
02/26/13 02:03 PM
02/26/13 02:03 PM
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Marysville, O-H-I-O
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Quote:

Quote:

Quote:

ok for cheap then, just get the solid .528 cam for the 383 & e85 quickfuel carb have the heads milled to get you to 12:1 or so (iron heads, alum could go to 13:1) run a 180 deg thermostat






Do you have any idea hom much would have to come off a set of heads to get his low compression 383 , he's lucky if it's 8:1 on its RATED 9.2 compression.

I just ran some numbers , the pistons in his engine are probably .080 in the hole , if this is the case he would have to have a head with a 46cc chamber to get 12.0 in a 383.

If his heads are 84cc he would have to cut .190 off them to get the chamber down to 46 cc.

It's a nice thought but not something doable with his low budget build with parts he has laying around .




there were different 383's some 10:1 some 9.5:1 some 8.5:1 etc.




you're talking advertised numbers I take it? what 383 was ACTUALLY a 10:1 compression?


the magnum will be about 9.0 compression with the stock heads and stock head gaskets. a .030 cut on the heads and a felpro 1008 gasket gets you 9.5 compression with the dished factory pistons. I actually measured mine while I had it open and I'm at 9.5 compression, assuming things like a 58cc head was actually 62 before being cut, and as accurately as I could measure the edge of the dished piston in relation to the deck at TDC.

anyway, budget minded, I still give the nod to the 383. a good intake, carb, cam, headers, and you have a 400-425hp motor on 89 octane gas. the magnum will cost a bit more money to get over 400 hp out of it.


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Re: 360 Magnum vs 383... What would make more power? [Re: Pale_Roader] #1393698
02/26/13 03:18 PM
02/26/13 03:18 PM
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Irving, TX
feets Offline
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Which transmission and converter do you have on hand? If it's B/RB stuff you'd be money ahead to stick with the 383.

A mild 383 and 5.9 Magnum are going to be very close in power. For some reason the 5.9 has always been a gas hog.


We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: 360 Magnum vs 383... What would make more power? [Re: 70Cuda383] #1393699
02/26/13 03:18 PM
02/26/13 03:18 PM
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Quote:

anyway, budget minded, I still give the nod to the 383. a good intake, carb, cam, headers, and you have a 400-425hp motor on 89 octane gas. the magnum will cost a bit more money to get over 400 hp out of it.






...and I think the weight difference is overrated; once you put on headers and an aluminum intake, the 383 isn't that heavy. A mini starter, alum water pump, etc. and it gets lighter yet. You could always go with a set of alum eddy's or stealths in the future too. I would bet that a 383 with all the alum goodies is as light as a stock LA setup.


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]
Re: 360 Magnum vs 383... What would make more power? [Re: 74yellowduster] #1393700
02/26/13 04:36 PM
02/26/13 04:36 PM
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JohnRR Offline
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Quote:

Quote:

Quote:

ok for cheap then, just get the solid .528 cam for the 383 & e85 quickfuel carb have the heads milled to get you to 12:1 or so (iron heads, alum could go to 13:1) run a 180 deg thermostat






Do you have any idea hom much would have to come off a set of heads to get his low compression 383 , he's lucky if it's 8:1 on its RATED 9.2 compression.

I just ran some numbers , the pistons in his engine are probably .080 in the hole , if this is the case he would have to have a head with a 46cc chamber to get 12.0 in a 383.

If his heads are 84cc he would have to cut .190 off them to get the chamber down to 46 cc.

It's a nice thought but not something doable with his low budget build with parts he has laying around .




there were different 383's some 10:1 some 9.5:1 some 8.5:1 etc.




And Chrysler OVERSTATED compression especially on 383's.

If you read the initial post he has a 67 383 and he says it's rated at 9.2, actual is closer to 8.2. I have a couple of 69 383 335HP road runner/superbee engines , it's rated at 10.0 , actual is more like 9.3 .

it's hard to build 12.0 in a 4.25 bore and a 3.375 stroke.

I have a 383 that is about 12.4 compression ... to get it , I had to increase the stroke to 3.9 , cut the heads down to 84 cc from 90 and put a 10 cc dome on the piston.

Re: 360 Magnum vs 383... What would make more power? [Re: 70Cuda383] #1393701
02/26/13 04:38 PM
02/26/13 04:38 PM
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JohnRR Offline
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Quote:


you're talking advertised numbers I take it? what 383 was ACTUALLY a 10:1 compression?





There isn't one as they rolled out the door of a Chrysler factory, the 335HP 383 in 68/69 is as close as they get with 9.3 actual.

Re: 360 Magnum vs 383... What would make more power? [Re: DPelletier] #1393702
02/26/13 04:39 PM
02/26/13 04:39 PM
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Someplace you aren't
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Do you already have the 383? Not going to recoup much if you dump it for a 5.9.


I want my fair share
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