Build me a 12 second 318 magnum
#1368637
01/12/13 10:58 PM
01/12/13 10:58 PM
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Joined: Oct 2011
Posts: 318
Fort Collins, Colorado
CoDart
OP
enthusiast
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OP
enthusiast
Joined: Oct 2011
Posts: 318
Fort Collins, Colorado
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Hi all, Im looking to build a budget 12 second 318 magnum. Keep in mind this will be at 5500ft above sea level, so about 1 second difference from sea level. I just love these 318s! Here is my build so far: 3000lb duster 904 trans with 4000 stall, 4.88 gears, 28" slicks '97 Magnum 318, stock bottom end -Heads home ported by me, milled and .025" head gasket for around 10.1-10.3 compression. Cam -Airgap intake -Headers, 2.5" exhaust -QuickFuel 950cfm carb Think this will break into the 12s? Thanks!!! 
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Re: Build me a 12 second 318 magnum
[Re: CoDart]
#1368638
01/12/13 11:17 PM
01/12/13 11:17 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Quote:
Hi all, Im looking to build a budget 12 second 318 magnum. Keep in mind this will be at 5500ft above sea level, so about 1 second difference from sea level. I just love these 318s! Here is my build so far:
3000lb duster
904 trans with 4000 stall, 4.88 gears, 28" slicks
'97 Magnum 318, stock bottom end
-Heads home ported by me, milled and .025" head gasket for around 10.1-10.3 compression.
Cam
-Airgap intake
-Headers, 2.5" exhaust
-QuickFuel 950cfm carb
Think this will break into the 12s?
Thanks!!!
Your looking at needed about 450 hp. Out of a 318 is asking for a bit much. The stock Magnum head is good for about 400hp. You think your home port is good for another 50? Don't forget the cam you chose will have different lift values based on the Magnum head's stock 1.6 rocker ratio vice the listed lift calculated for a 1.5 ratio. You will need to pay close attention to the retainer to guide clearances. Since you have a stock bottom end pay attention to valve to piston clearances too.
Now if you were at sea level, then yes it'd be doable as the HP requirement drops.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: Build me a 12 second 318 magnum
[Re: terzmo]
#1368643
01/13/13 03:18 PM
01/13/13 03:18 PM
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Joined: Oct 2005
Posts: 1,305
Lakewood, Colorado
herkamer
pro stock
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pro stock
Joined: Oct 2005
Posts: 1,305
Lakewood, Colorado
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Years ago one of my friends had a 100k+ mile 318 with a B&M 144 supercharger running 7 or so lbs of boost in a 68 Barracuda and the best it could manage was in the 14's at this altitude. Traction was a huge problem, even with 400lbs of tools in the trunk. Once he went to a 11:1 360 (purely experimental quench motor) he was able to get into the mid 13's. 12's at this altitude is very hard to get, especially without displacement. My brothers 6 pack Road Runner would only run high 14's here. A stock 383 B Body is a high 15 second car here.
Matt
69 Dart Swinger 340
83 W350, Megasquirted with 46RH
Old news: 72 Demon street/race mobile
Latest: 70 Duster backhalf car
and even more
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Re: Build me a 12 second 318 magnum
[Re: MPerry]
#1368645
01/13/13 03:32 PM
01/13/13 03:32 PM
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Joined: Oct 2005
Posts: 1,305
Lakewood, Colorado
herkamer
pro stock
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pro stock
Joined: Oct 2005
Posts: 1,305
Lakewood, Colorado
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Terminal velocity might get it there!  Forgot to add this: My brother also had a 67 Barracuda. All fiberglass except for the quarters and roof and aluminum inside, weighed in around 2100lbs if my memory is good. 12.5:1 340 with a 904, W2 heads and some lumpity cam and it would run 11.2 consistently. But that's full blown race car and it was pushing 550+ HP. Budget+12 seconds isn't gonna go together very well here. And it's realistically closer to about a 1.5-2 second loss coming up here from sea level.
Matt
69 Dart Swinger 340
83 W350, Megasquirted with 46RH
Old news: 72 Demon street/race mobile
Latest: 70 Duster backhalf car
and even more
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Re: Build me a 12 second 318 magnum
[Re: herkamer]
#1368647
01/13/13 03:58 PM
01/13/13 03:58 PM
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Joined: Oct 2011
Posts: 318
Fort Collins, Colorado
CoDart
OP
enthusiast
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OP
enthusiast
Joined: Oct 2011
Posts: 318
Fort Collins, Colorado
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Thanks for all the replies!  I have faith I can get to those 12s. I used to have a LA 318 with magnum heads, xe262 cam,eddy performer, headers, 3.91, 904 stock stall, 195/75/14 tires,3500lb dart, it was running 15.0s@92mph then that engine got replaced with a RHS headed 360, airgap intake,small roller cam, 3.91 gears, 3500 stall,3450lbs it was running 13.8s@97mph.These were all at about 8500 D/A. Im thinking a 3000lb low geared, high stalled, cammed 318 Duster should get me very close, on a cold day! I could always 
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Re: Build me a 12 second 318 magnum
[Re: CoDart]
#1368648
01/13/13 04:22 PM
01/13/13 04:22 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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Gonna have valve to piston clearance issues if it is really 10 to one with stock pistons (no valve releifs) and that cam. A switch to KB167 pistons will help get the compression up even more and give you some valve to piston clearance and quench. At that high of elevation your compression is more like 9 to 1, not near enough for that cam.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Build me a 12 second 318 magnum
[Re: CoDart]
#1368649
01/13/13 04:31 PM
01/13/13 04:31 PM
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Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
TC@HP2
master
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master
Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
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Quote:
Thanks for all the replies!
I have faith I can get to those 12s. I used to have a LA 318 with magnum heads, xe262 cam,eddy performer, headers, 3.91, 904 stock stall, 195/75/14 tires,3500lb dart, it was running [Email]15.0s@92mph[/Email] then that engine got replaced with a RHS headed 360, airgap intake,small roller cam, 3.91 gears, 3500 stall,3450lbs it was running [Email]13.8s@97mph.[/Email]
These were all at about 8500 D/A.
Im thinking a 3000lb low geared, high stalled, cammed 318 Duster should get me very close, on a cold day! I could always
Low gear, high stalled, lightweight, you might crack 12.90s. This may not be a very streetable combo from a 318 though. The difference between your 318 and 360 builds above was significant and will take a fair amount of effort to better the 360 performance with a 318.
My combo for 12s in Denver was a 360 with later swirl port heads, 11.5:1, .590 lift cam, tarantula intake, 750 carb all stuffed in a 3000# chassis with 4200 stall and 4:56 gears turning a 29" tire, SS springs, skinny t-bars without sway bar, and drag shocks. This would e.t. at 12.2 and m.p.h. at 108-110.
The exact same driveline combo in my street oriented 3200# car with big t-bars and sway bars would only run 13.2. So I had a difference of a second in e.t. by dropping 200# and going with a dedicated drag race suspension.
This mill cost around $5k to build in the mid 90s and lasted about 15 years before it fragged a bearing. Is that budget? Depends on where you're comming from.
Big issue to the combos here is compression. Getting it high enough to compensate for the altitude usually means race gas or water injection. Or butt loads of mechancial advantage (gears and stall) to make up for it.
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Re: Build me a 12 second 318 magnum
[Re: TC@HP2]
#1368650
01/13/13 05:19 PM
01/13/13 05:19 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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Quote:
Quote:
Thanks for all the replies!
I have faith I can get to those 12s. I used to have a LA 318 with magnum heads, xe262 cam,eddy performer, headers, 3.91, 904 stock stall, 195/75/14 tires,3500lb dart, it was running [Email]15.0s@92mph[/Email] then that engine got replaced with a RHS headed 360, airgap intake,small roller cam, 3.91 gears, 3500 stall,3450lbs it was running [Email]13.8s@97mph.[/Email]
These were all at about 8500 D/A.
Im thinking a 3000lb low geared, high stalled, cammed 318 Duster should get me very close, on a cold day! I could always
Low gear, high stalled, lightweight, you might crack 12.90s. This may not be a very streetable combo from a 318 though. The difference between your 318 and 360 builds above was significant and will take a fair amount of effort to better the 360 performance with a 318.
My combo for 12s in Denver was a 360 with later swirl port heads, 11.5:1, .590 lift cam, tarantula intake, 750 carb all stuffed in a 3000# chassis with 4200 stall and 4:56 gears turning a 29" tire, SS springs, skinny t-bars without sway bar, and drag shocks. This would e.t. at 12.2 and m.p.h. at 108-110.
The exact same driveline combo in my street oriented 3200# car with big t-bars and sway bars would only run 13.2. So I had a difference of a second in e.t. by dropping 200# and going with a dedicated drag race suspension.
This mill cost around $5k to build in the mid 90s and lasted about 15 years before it fragged a bearing. Is that budget? Depends on where you're comming from.
Big issue to the combos here is compression. Getting it high enough to compensate for the altitude usually means race gas or water injection. Or butt loads of mechancial advantage (gears and stall) to make up for it.
You can run a lot higher compression on the same octane in high elevations because there is less air density, you are just compressing it to the same density as it would have been at sea level, this merely helps cover up some of the loss.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Build me a 12 second 318 magnum
[Re: CoDart]
#1368651
01/13/13 05:43 PM
01/13/13 05:43 PM
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Joined: Aug 2003
Posts: 475
hobbs, new mexico
SixDRacing
mopar
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mopar
Joined: Aug 2003
Posts: 475
hobbs, new mexico
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3100 lb duster with driver,3500 convertor, 904, 4.10 gears with posi, .030 over 318. 10:1 cr, at 5000 ft air, went 12.97 shifting at 5000.
engine had a cast crank, 273 light rods (575 grams) with arp rod bolts, mopar pistons P4876968, hyd roller cam (226/226 at .050 lift, .510/.510 lift with 1.5 rockers, and 110 lobe seperation.) i self ported a set of 915 heads with 2.02/1.60 valves. i used a m1 single plane intake and a 700cfm holley. i believe an preformer air gap would have worked better.
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Re: Build me a 12 second 318 magnum
[Re: herkamer]
#1368653
01/13/13 06:55 PM
01/13/13 06:55 PM
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Joined: Mar 2005
Posts: 2,060
Pendleton NY
terzmo
top fuel
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top fuel
Joined: Mar 2005
Posts: 2,060
Pendleton NY
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Quote:
Years ago one of my friends had a 100k+ mile 318 with a B&M 144 supercharger running 7 or so lbs of boost in a 68 Barracuda and the best it could manage was in the 14's at this altitude. Traction was a huge problem, even with 400lbs of tools in the trunk. Once he went to a 11:1 360 (purely experimental quench motor) he was able to get into the mid 13's. 12's at this altitude is very hard to get, especially without displacement. My brothers 6 pack Road Runner would only run high 14's here. A stock 383 B Body is a high 15 second car here.
14 seconds is what a stock 6pak did in 69..no surprise...
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Re: Build me a 12 second 318 magnum
[Re: CoDart]
#1368654
01/13/13 07:11 PM
01/13/13 07:11 PM
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Joined: Jun 2008
Posts: 1,822
Colorado
denfireguy
top fuel
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top fuel
Joined: Jun 2008
Posts: 1,822
Colorado
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Race it in Pueblo. Cars from Bandimere go much faster down there. Albuquerque as well.
pueplomotorsportspark.us
Amazing how a little more air helps.
Craig
2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado
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Re: Build me a 12 second 318 magnum
[Re: terzmo]
#1368655
01/13/13 07:14 PM
01/13/13 07:14 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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Race my 71 Demon at Top Gun Raceway last year, the corrected DA was usually around 6500 ft. The car ran 11.30s at best...When to Sacramento Raceway in early Sept the DA was 1500 at worst..the same car ran 10.72.. 6 tenths difference with no change except jets... 3000 lb car with driver.
At your elevation you are going to need a car that can run at least a full second faster then what you actually get.
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)
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