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Re: 69-383 Motor not making enough low end torque
[Re: furious70]
#624414
03/02/10 07:19 PM
03/02/10 07:19 PM
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Joined: Feb 2009
Posts: 1,149
NW New Jersey
RSI700VIPER
super stock
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super stock
Joined: Feb 2009
Posts: 1,149
NW New Jersey
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You can advance the cam timing to get more low end power. Hopefully the cam was dialed in correctly. If not, that could be the source of your problem. I put a MP cam in a motor once that needed a 6 degree offset bushing to center it. I would never buy a MP cam again. Pure junk.
1970 Superbird 440 Six BBL, 4-Speed, Dana, FJ5
1969 Daytona Charger 440 4-Speed, Dana, EV2
1971 340 Challenger Conv. Flemington Speedway Pace Car, FC7
1970 340 Six Pack Callenger T/A 4-speed T8 Tan
1971 340 Challenger RT Formal Roof, EV2 w/ V2 Stripe & Orange Houndstooth
1969 Talladega Torino, 428CJ
1969 Gurney Special Cyclone Spoiler II, 351 Cleveland
"Id rather have a bottle in front of me than a frontal lobotomy" Ben Franklin 1755
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Re: 69-383 Motor not making enough low end torque
[Re: 68 Dart GTS]
#624416
03/03/10 07:31 AM
03/03/10 07:31 AM
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Joined: Aug 2005
Posts: 65
Adelaide, SOUTH Australia
REDNICK
member
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member
Joined: Aug 2005
Posts: 65
Adelaide, SOUTH Australia
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I just installed a FBO dizzy advance limiter kit in my Coronet R/T with a solid 290 comp cammed 512/4sp/3.9. Local pump gas is 98 octane.(Australia) In my application, I limited it to 14 deg total so I can run about 20 deg initial running to about 34 total.Vacuum advance not used in my case. Also the advance springs were changed to delay the total to about 3k to compensate for the heavy car. It went pretty good before, but it goes like a raped ape now...and revs VERY cleanly with no real chance of detonation with the low total advance number (my engine has high comp and alloy heads also-iron heads and lower comp would be better with up to 38(?) deg.) Good kit for less than 40 bucks.Easy to install-good instructions From "4secondsflat.com" guy..... NEW From FBO "Do it Yourself Advance Limiter Kit #J685 This kit contains our Exclusive and Patent Pending Advance Limiter Disc, RPM springs, complete step by step Full Instructions and our 47 Page Spiral bound" "Tuning Guide" 
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Re: 69-383 Motor not making enough low end torque
[Re: 68 Dart GTS]
#624417
03/03/10 08:54 AM
03/03/10 08:54 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:
The cam degree was put in TDC, It's just a weekend cruiser not a race motor, i have some buddys with stroker 440's with alot more power and other Mopars with pretty much stock motors and they where installed TDC without advancing it and they run like a bat out of hell.
What am i missing on degreeing the cam for street use. Also any suggestions on who re-curves dist. in the Houston, TX. or surronding area's.
Thanks for all the imput, you guys have been alot
of help and carry the Mopar banner very well...
where the cam is installed at (intake centerline) has the major impact on where the intake valve closes, which is what determines cylinder pressure. cyl pressure determines torque for the most part.
for an XE274, it's ground with a 110 degree LSA, but with 4 degrees of advance built in, so if it was degreed in to verify intake centerline, it should be at 106 degrees after top dead center (ATDC). that puts the intake close point 63 degrees after bottom dead center (ABDC). compare to a comp XE268, which has the intake close point at 60 degrees ABDC.
now assuming you used the KB flat tops at 0 deck, 906 (usually 90-92cc) heads, and a thin MP head gasket, that yields a true compression ratio of ~8.8:1. using one of the online dynamic compression ratio calculators, and plugging these assumptions in, the dynamic compression of this motor end up being ~7.1:1...by advancing the cam 4 degrees, the DCR jumps up to 7.3:1....advancing the cam will move the powerband down in the RPM range, giving a boost in low end and midrange, and a slight cost in the top end (how much time do you spend at 5500-6000 RPM anyway?)
in essence, it'll make your XE274 behave a little more like the smaller XE268.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 69-383 Motor not making enough low end torque
[Re: 68 Dart GTS]
#624430
04/18/10 01:18 AM
04/18/10 01:18 AM
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Joined: Nov 2009
Posts: 2,275
Desert Tracker
HYPER8oSoNic
top fuel
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top fuel
Joined: Nov 2009
Posts: 2,275
Desert Tracker
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Quote:
Mopart guys, i'm having very low end torque problems. I have a 68 dart 383. It is pretty much stock but bored 30 over, schumacher headers, 383 torker mainifold with a new holley 770 avenger carb, new Comp. XE274 cam and lifters, stock heads ported and polished with HD springs, new pushrods, rebuilt 727 trans, 323 sure grip and 3000 hughes stall converter, stock elct. ignition with orange ECU box. Everything is pretty much new in the motor, compression test is good, vac.is good but it's totally a dog on the low end out of the hole. the motor runs great and it seems to make good power but it just seems like its not getting the power to the rear wheels at launch. I'm starting to think the new in the box stall converter which i bought from a friend may be clogged or have trash in it. Any suggestions are similar problems and fixes would greatly be appreciated. I have gotten pretty frustrated and don't want to just keep throwing more money at it and hope the problem gets solved. Compression is approx 9.5 - 1 to 10-1,vac.@ 14, intl., dist. @ 12. Thanks.
Go with the 4.10's. It is a trade off: noise/poor
mileage vs. great street/track performance. If you
are looking for a "true dual-purpose car", you will need an overdrive tranny or unit. Along with
the 4.10's, you have a choice. Either you can make the Torker work with a SMALLER carb (650cfm)
or go with the Eddy RPM manifold and your current
770 cfm carb. Optimize the power valve/jetting in either case.
Try to get your ignition at 35-38
deg. total at in by at least 2200rpms. Double check your compression ratio, since it is possible to have something closer to high 9's. You
did not indicate if you had ZERO DECK height or not. The
total timing may be affected by this factor.
Food for  . That lightweight A body should be running, at the least, very low 12's. :twocents
Last edited by HYPER8oSoNic; 04/18/10 01:24 AM.
"Stupidity is Ignorance on Steroids"
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