Demon et help
#2081571
05/27/16 11:06 PM
05/27/16 11:06 PM
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Joined: Mar 2015
Posts: 19 mass
SS/ Demon
OP
member
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OP
member
Joined: Mar 2015
Posts: 19
mass
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I have a 71 dodge demon 340 dedicated drag car that I brought to the track this past weekend and did not get the results I was looking for despite lots of tuning time. I wanted to know if the goal of 10.90s seems reasonable given my specs. The car weighs 2900 lbs with driver. It is a 345 cubic inch small block with h beam rods, mopar performance crank, stock stroke, 13.5:1 compression, with 0 deck height, and fully race prepped j heads. .040 off the heads, 2.02 intake, 1.60 exhaust, mechanical full roller crower cam pn 31409 with spec at dur @ .050) lift 268,274 @ 50 with 106 lobe center, and a gross of valve lift with 1.5 rocker with .645/ .623. supposed to be good up to 8250 rpms. It runs an Edelbrock super victor jr with mild porting and a holley 950 double pumper with 80 jets in the primary and 88s in the secondaries. The ignition is an electronic tach drive distributor with tailor pro wires msd digital 6al and a Mallory performance coil. the convertor is an 8 inch 5500 stall unit coupled to a 904a fully race built, with a billet drum, bolt in sprag, manual valve body, rollerized, etc. It was at the time of the track utilizing 456 rear gears. I have since ordered 513 rear gears in hopes of upping my trap rpm and speed. It has a spooled 8.75 Chrysler with ladder bars and super stock springs using only 2 leaves per side. It is running a 30 x 10 inch slick in the rear and leaving off the foot brake. the fuel system is .5 inch from tank to regulator at the carb with a holley black pump. the hedders are 1.75 to 3 inch collectors with an 8 inch extension on them.
the car this past weekend ran a best et of 11.86 at 111.92 mph. it ran a 1.619 at the 60 foot and 4.752 in the 330 foot. it ran a 7.426 in 1/8 mile at 91.9 mph. it ran a best of 9.803 at the 1000 foot mark. these times are the best overall times for each marker. I shifted the car between 72-7500 rpms as well as launching off the foot break between idle-3000 rpms with greater success coming with a higher rpm launch. Again, would a low 11, 10.99 time be an unreasonable goal with some more tuning and weight reduction?
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Re: Demon et help
[Re: SS/ Demon]
#2081585
05/27/16 11:42 PM
05/27/16 11:42 PM
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Joined: Feb 2005
Posts: 20,203 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,203
PA.
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I hate to come straight out and tell you this but something is wrong with your combo and did you try shifting at a lower RPM? Here's my Sons combo. (1970 Duster) .040 over stock crank 360 set of Edelbrock heads I ported Victor intake I ported 520 lift Racer Brown solid cam 11.2-1 compression flat-tops H beem K1 rods 750 alcohol carb 1 7/8 headmen headers 4.10 rear geat 10-28 slicks shifted at 6400 RPM 727 transmission with 5400 stall 34 degree locked out timing footbrake car 3150 pounds 10.50-10.60's at Pittsburgh Raceway Park not some east coast SUPER track. very basic low maintenance combo
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: Demon et help
[Re: SS/ Demon]
#2081608
05/28/16 12:27 AM
05/28/16 12:27 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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My car is lighter but when I ran a stock stroke with W-2s I ported and a 260/270 .640/.640 on a 105lsa installed at 103 with a 727 and 5600 stall and 4.88 gear with 14x31 slicks I ran a best of 9.90 but I had to keep it at 10.0 or slower.. my headers I built were 1 7/8 with a 3.5 collector 18" long.. I was turning 8100 rpm... what are your heads like do you know what they flow
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Re: Demon et help
[Re: MR_P_BODY]
#2081624
05/28/16 01:08 AM
05/28/16 01:08 AM
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Joined: Oct 2009
Posts: 1,267 North, Alabama
D-50
pro stock
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pro stock
Joined: Oct 2009
Posts: 1,267
North, Alabama
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I had almost the same combo in my street car.My 72 Demon had a .030 over 360 with Hughes Engines stage 2 ported J heads (flowed 265 cfm) 13.5 comp. a Hughes Engines solid cam with 1.6 rockers (265/270 @ .050, 642/656 lift cam). It was a stock interior bench seat all steel except hood with no roll bar (3450 lbs). 750 carb , 5000 stall 8 in PTC convertor, 486 gears driven to track (130 miles round trip). My best ET on motor was 6.99 @ 96 mph. On 100 shot NOS (47/53 jets) spinning it ran a 6.47 @ 106 mph.
1.33 60 ft,6.21 at 110.59 in the 1/8, pump gas small block,2950lbs,drag radials,mufflers and driven to track ...
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Re: Demon et help
[Re: SS/ Demon]
#2081637
05/28/16 01:21 AM
05/28/16 01:21 AM
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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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At 112 mph you are running an ET for that MPH...something wrong...
check timing..is the carb opening all the way?
dont think 5.13 are going to do you any good...
how tall are the rear tires?
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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Re: Demon et help
[Re: SS/ Demon]
#2081644
05/28/16 01:39 AM
05/28/16 01:39 AM
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Joined: Jan 2003
Posts: 11,729 Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,729
Portage,michigan
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It runs almost the numbers my 10.5 to 1 318 runs with a hydraulic cam( except I am 500 pounds heavier)
To run like that, must be the heads aren't any good, can't think of anything else for a car that runs the right number for the ET.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight 418 BPE factory replacement headed stroker, 565 lift solid cam Best so far, low 10.30’s 1/4 1.41 best 60 foot 6.56 at 104.17
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Re: Demon et help
[Re: SS/ Demon]
#2081673
05/28/16 03:28 AM
05/28/16 03:28 AM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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I would agree that its down on power. My old 340 Dart that I ran back in the 70's and early 80's ran about as good. It was a 66 Dart I put a 340 in that was a stock bore and piston 340 as a matter of fact it was a stock shortblock that I just rebuilt. The heads were stock 340 heads that I ported some and I milled .030 to raise the comp as I used the factory stock pistons rated at 10.5 but I never actually cc'd everything. I ran a Crower solid flat tappet of .500 and .510 lift and 284 & 300 advertised duration. Stock 273 rockers with lock nut adjusters. Used the Holley Strip Dominator intake and a 700 DP. JR headers and it was a stock 4-speed with 4.56's and a 28.5 x 9 slicks. Car was all metal and all there so I guessed it weighed about 3000 to 3400 lbs. It ran a best of 11.94 @ 113 mph in 1981 as I rolled the car in early 1982. I would think your car would make more power and more mph then mine did. It seems something has your eng down on power some. Ron
Last edited by 383man; 05/28/16 03:31 AM.
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Re: Demon et help
[Re: MR_P_BODY]
#2081700
05/28/16 08:54 AM
05/28/16 08:54 AM
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Joined: Mar 2015
Posts: 19 mass
SS/ Demon
OP
member
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OP
member
Joined: Mar 2015
Posts: 19
mass
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I don't know any flow rate on the heads. All I know is they are ported very heavily for cast iron j heads with a ton of bowl work
Last edited by SS/ Demon; 05/28/16 09:00 AM.
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Re: Demon et help
[Re: SS/ Demon]
#2081704
05/28/16 09:02 AM
05/28/16 09:02 AM
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Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
master
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master
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
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Take some timing out of it. Shift closer to 7,000 rpm. You had one 1,000 ft mark of 9.80. Good numbers. Shouldn't have taken 2 more seconds to go another 300 ft. Try and duplicate your driving sequence for that run. Are you running a power valve in the carb? Large spread on jetting. As already mentioned, check for full throttle opening.
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Re: Demon et help
[Re: SS/ Demon]
#2081785
05/28/16 12:21 PM
05/28/16 12:21 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Make sure the wires on 5 and 7 arent backwards it wont sound like a miss but will be way down on power... as me how I know.. since they fire next to each other
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