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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: Dakota_Don]
#610695
02/11/10 06:41 PM
02/11/10 06:41 PM
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Joined: Jul 2003
Posts: 6,167
Maryland
GO_Fish
master
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master
Joined: Jul 2003
Posts: 6,167
Maryland
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1 hp/ cubic inch used to be hard to achieve back in the day, but should not be a problem now with the right parts and good breathing heads.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
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01 3.5L 300M 16.23@ 86.97 mph
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: Dakota_Don]
#610696
02/11/10 07:44 PM
02/11/10 07:44 PM
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Joined: Dec 2003
Posts: 22,696
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
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Heads are horsepower, which heads are we comparing?
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: DusterKrazy]
#610699
02/12/10 12:17 AM
02/12/10 12:17 AM
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Joined: Jan 2003
Posts: 20,172
Park Forest, IL
slantzilla
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,172
Park Forest, IL
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Here's a link to a thread on the S/SS board. Tons of great info there. http://www.classracer.com/classforum/showthread.php?t=17876&highlight=D-DartBasically, if you get heads that flow as well, and intake the works as good, the same compression, and the same camshaft, a 318 should actually run better than a 273. The 273 D-Dart is kinda like the Hyper-Pak Slant, more legend than fact. 
"Everybody funny, now you funny too."
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: Jim_Lusk]
#610701
02/12/10 02:14 AM
02/12/10 02:14 AM
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Joined: Jan 2007
Posts: 1,668
Mi,U.S.A.
mike s
top fuel
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top fuel
Joined: Jan 2007
Posts: 1,668
Mi,U.S.A.
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Camcraft ground the original cams for the D-dart.Last I checked they are still in business.
Leave the gun.......take the Cannoli's....Mike
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: jcc]
#610703
02/12/10 10:05 AM
02/12/10 10:05 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Heads are horsepower, which heads are we comparing?
 a 273's 3.625" bore really limits valve size to 1.78/1.5...you'd have to do a lot of work on a set of 273/318 heads to get them to flow comparable to even a stock magnum head. IIRC 1.88" valves need cylinder notching for clearance, I know 1.92" magnum valves do on a 273....
the 318's bore will fit more valve area, and IMHO the magnum sized valves are about ideal for that bore, as a trade off between curtain area and valve shrouding. a 318's bore will fit 2.05 intakes without notching for clearance.
build the 2 engines identical (cam, compression, heads, intake, etc) and the 318 should make ~16% more power, because of 16% more displacement. that would put the 'teen at about 320-325 HP.
the engine I built for my car, I'm guessing, is making about 320-330 HP conservatively. it's a stock '86 roller short block, pistons .055" in the hole, roller cam reground with bullet's HR259/316 lobe (259 adv, 208 at .050, 127 at .2" lobe lift) for both the intake & exhaust, OEM mag heads ported by me following dulcich's magnum porting article from the may '05 (IIRC) mopar muscle, thin head gaskets (results in 9:1 comp), headers, eddie RPM air gap, and an eddie 600 carb.
I can make as much power with a MUCH smaller cam than the theoretical D-dart 318 for a few reasons:
1) HEADS. low lift flow is a function of the curtain area of the valve. a larger valve should have better low lift flow. peak flow of the magnum heads ported by dulcich was ~235intake/185 exhaust in the .5" lift range. OEM 273 heads ('920 castings) are probably in the 150/120 int/ex with peak flow in the .450" lift range.
2) cam. the newer hydraulic rollers like mine can be pretty aggresive, especially compared to the ramps of the 60's. comparing my roller cam to a "modern" aggressive flat tappet hydraulic, an XE262, while my .050 dur is 10 degrees smaller, my .2" dur is only 3 degrees smaller, and my lobe lift is .008" higher, coupled with the magnum's rockers, I have .506" lift, with only 259 degrees of adv duration.
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: chewy]
#610705
02/12/10 02:23 PM
02/12/10 02:23 PM
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Joined: Feb 2003
Posts: 16,133
Mesa, Arizona
dart4forte
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 16,133
Mesa, Arizona
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Quote:
From all I've gathered on the d-dart spec's and numbers, they were for race-only application purchases from dodge.
The cam and holley were installed in a 10.5:1 compression 273, with the single plane intake and dual point ignition. it was only a special option in '66.
There isnt anyone out there that I've found that has a Spec or can grind a D-Dart Cam. I contact a number of custom grinders, and a few of them even told me that if I found one in an old race car to let them know and they'd pay for me to send it to them so they could duplicate it.
I have yet to see a car with the d-dart package confirmed installed on the car. So if you are lucky enough to find one, snag it.
I got one ground for my 64.
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: dart4forte]
#610706
02/12/10 02:33 PM
02/12/10 02:33 PM
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Joined: Feb 2003
Posts: 16,133
Mesa, Arizona
dart4forte
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 16,133
Mesa, Arizona
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Quote:
Quote:
From all I've gathered on the d-dart spec's and numbers, they were for race-only application purchases from dodge.
The cam and holley were installed in a 10.5:1 compression 273, with the single plane intake and dual point ignition. it was only a special option in '66.
There isnt anyone out there that I've found that has a Spec or can grind a D-Dart Cam. I contact a number of custom grinders, and a few of them even told me that if I found one in an old race car to let them know and they'd pay for me to send it to them so they could duplicate it.
I have yet to see a car with the d-dart package confirmed installed on the car. So if you are lucky enough to find one, snag it.
I got one ground for my 64.
if you have any questions regarding the D/Dart you should talk with ddartdude@aol.com.
he's owned several D/Darts and know several who raced them back in the day.
As far as heads, I'll stick to my 920s. We can get some pretty good flow numbers out of them.
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: Jim_Lusk]
#610708
02/12/10 06:10 PM
02/12/10 06:10 PM
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Joined: Jan 2003
Posts: 6,816
Alton, IL
Dakota_Don
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,816
Alton, IL
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Quote:
I've seen one in person (and was able to drive it, although it was somewhat detuned) and know of a few others. The only thing special on the heads are the valve springs. Otherwise they are stock 66 273 parts. There are probably several cams out there that can be used in place of the original (I believe there are specs in the TSB, which I have here).
thats what i heard about the 273 heads, so if i used the 318 heads with good VS and a cam simular to the D dart, intake,carb and headers the 318 should make approx 318 HP with nothing more then a cam swap and 4brrl intake and carb..
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: Dakota_Don]
#610710
02/12/10 06:17 PM
02/12/10 06:17 PM
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Joined: Feb 2003
Posts: 16,133
Mesa, Arizona
dart4forte
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 16,133
Mesa, Arizona
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Quote:
Quote:
I've seen one in person (and was able to drive it, although it was somewhat detuned) and know of a few others. The only thing special on the heads are the valve springs. Otherwise they are stock 66 273 parts. There are probably several cams out there that can be used in place of the original (I believe there are specs in the TSB, which I have here).
thats what i heard about the 273 heads, so if I used the 318 heads with good VS and a cam simular to the D dart, intake,carb and headers the 318 should make approx 318 HP with nothing more then a cam swap and 4brrl intake and carb..
What you have to do is experiment with the heads and know someone with a flowbench. You can get a larger valve without the shrouding. you can do a lot of work with bowl blending, port matching and smoothing,. The key is to get the maximum velocity.
We have numbers that show the 920's flow as well or even better than the 302's with a little work. there's a couple of Stock Eliminator racers that run 273s that stop by now and then. As far as that cam, you'd be best off to run with a 4 speed. If not you'll need a fairly loose converter.
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: Dakota_Don]
#610711
02/12/10 06:22 PM
02/12/10 06:22 PM
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Joined: Jan 2003
Posts: 6,816
Alton, IL
Dakota_Don
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,816
Alton, IL
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hers my plan, stock 68 318, mag heads, cam simular to the D dart, with the 1.6 rockers added into lift of a cam..headers, 904, same gears as a the D dart..holley carb like the d-dart..
what do you think, pluss learning about this D dart is kool.. s sounds like a bad assss dart back in the day..
if anyone has any more info, dyno numbers,times ect.. and of course photos too..
here is a short story, accorrding to the author the D-dart had different heads, larger valves ect..
thanks to all who posted.
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Re: 273/D dart engine specs /vs 318 with same specs??
[Re: dart4forte]
#610713
02/12/10 07:18 PM
02/12/10 07:18 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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I did a stock re-ring and bearing on a '71 318 and put milled 360 heads on it with a 480 lift 284 duration cam.
Motor was a dirt cheap rebuild and easily made 300 hp.
Very steet friendly and fun at the dragstrip too!
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