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#1
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I dont know what I'm doing wrong but something is wrong.I have a '72 dart swinger. Here are My specs:
440 .30 over Car and driver: 3500lbs 11.74 110mph qtm. 1050 Holley Dominator carb. with #88 jets single holley blue pump M1 single plane intake 902 head castings, big valves ported with Mopar templets 11.5 to 1 compression solid lift cam MSD distibutor MSD box 2 1/8 headers 4500 stall converter 727 automatic manual reverse, reverse pattern Dana 60 rearend with 5:13 gears 14x32 slicks Quarter Mile Times: 60ft: 1.571 330ft: 4.747 660ft: 7.440 at 90.764 MPH qtm: 11.801 at 110 MPH Is the anything you can think that I need to change or add to make my performance better?? PLEASE HELP!!! ------------------ John Stanton |
#2
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I'm wondering just what is scrubbing mph off at the top end. Losing fuel? Hoodscoop problem? Running a GER converter? I'd probably start by making the heads a known quanity (know your HP potential). What cam are you using? Your question is too vague given the information you provided as some ported heads are worse than stock ones. Also, 11.5 pistons yeilded only 9.8:1 cr in the last 440 I went thru. By taking a closer look that the parts are what you say they are you can eliminate alot of variables. Given the stuff your using you may not be far from it running the best it can.
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#3
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also what rpm are you running though the traps?
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#4
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We need more details about your set up. Cam specs, valve spring specs, torque converter brand/diameter, fuel line sizes, etc. Are you running race fuel?
Right now I am concerned about something limiting power at higer rpms (above 5500), maybe weak valve springs, insufficient fuel pressure, too small a cam etc. That is a lot of gear you are running even with 32" tires, especially for a 440. |
#5
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The consitency of the replys from both the Performance and Drag Racing pages is awesome. I think everyone has the same concern in both pages; top end HP - fuel delivery, tuning, mismatched parts, etc.
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#6
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I'd be looking into suspension problems also a 1.57 short time isn't that great. That combination should be in the neighborhood of 1.40 to 1.45. I also agree that there isn't enough info. good luck
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#7
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1050 dominator is a lot of carb for your 440. You need to turn alot of rpm to see any benefit from a dominator. I found that my 440 12-1/2-1 cr 915 ported & polished M1 single plane ran better with a 835 holley. With the dominator it used alot of gas and would run a total of 2 10s quicker in the evening when it started getting cooler. Hard to dial. The 835 would change 3 to 4 100s from the heat of the day to the cool nights.
Regards, ------------------ 66 Belv 440 auto 10.76 @125 69 RR 426 wedge auto 9.69 @ 140 |
#8
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Hard to say?
What are the cam specs and engine RPM range. What is your RPm at the end of the 1/4 mile? What is your Fuel pressure at the end of the 1/4 mile? Just guessing either your hitting top end RPm too soon, or the engine is loosing top end power. At first I thought you may have too much gear, but then I noticed you have really tall tires, so that may not be a problem. There is the possability the converter has excessive slippage at top end? If the engine is loosing power, it may be the fuel system. What size lines? are you using a fuel cell with a sump? In the carb, do you have the correct Primary power valve? Too low a value can close on top end leaning the engine out. For a strip car plug the rear PV and jet up. Make sure to use jet extentions on the rear jets too. I think the Holley pump may also be on the small side for a 11-second car, you may need a higher pressure pump and a fuel system with a bypass regulator mounted up at the engine. The higher pressure to the front mounted bypass regulator eliminates the pressure drop in the fuel lines caused by the G-force acting on the weight of the fuel in the lines. |
#9
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I lost my cam specs but the cam is a Cam Motion. the grind # is 52642-2682-09. I don't know if that helps but there it is.
Here are the other things asked Single Holley Blue pump with 1/2" fuel lines 906 heads: 2.14 intake 1.81 exhaust Ported with Mopar templets 1,6 Roller rockers-Crane Cam Headers-Pro Parts-2"x36" tubes 8" Wilson converter 727-auto - reverse pattern - trans brake I leave the line at 4500rpm shift at 6800rpm cross line at about 6200rpm I tried a Braswell Holley 750 and it ran the sam as my Dominator. Thanks for your help I NEED IT!!! |
#10
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I'd bet on valve float. There are really a lot of possibilities, your best chance of tracking it down quickly would be a dyno session.
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#11
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This is just a guess, but by looking at the part number, I think the cam is 264° @ .050" on the intake and 268° @ .050" on the exhaust with a lobe separation of 109°. If that is the case, then I would wonder if the cam wasn't just a little too big for your compression ratio.
I just checked it on Engine Pro and it is only 2° too big for the compression ratio of 11.5:1. The question is whether or not you really have 11.5:1? If you have much less than this, the engine will lose torque and hp over the optimum sized cam, which would be a problem in a 3,500 lb car. BTW I assumed that the 5 was for the engine style, 2 for the master prof |
#12
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I'll go with some of the consensus; you need more compression than 11:1 to get that cam to pull at the higher rpm range. Check your valve springs for correct weight and make sure they are not in coil bind or interference with valve guides/seals. Do you have top end miss or buzzing sound? Your jets also seem a bit small for the rpm range as well. I would expect them to be in the 90's size for the air necessary at ~6800. Has the carb been reworked for racing? Consider backing off the rearend ratio to maybe 4.9:1. Whose slicks and how much air pressure at launch? What is your pinion angle and are you running leaf springs, ladder bars or four link? You are probably really nose heavy @ 3500 lbs and are skating around like I used to do. Is the back end tubbed? How much roll cage do you have and is it tied to the front frame rails? Don't fret, this is fixable. It will just take some time to work thru the list. What E.T. and mph do you think you should be running? I think you have a legit 10 sec car just need to get it down there.
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#13
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Try a bigger fuel pump, maybe the Holley Black pump.
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#14
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First, I must say that the car runs good 60 ft times; if it didn't it would et much worse. This kind of pulls the carpet under the too big carb/cam/too low CR. Our cars run 11.1's with 1.61-1.63 60 ft times. First thing I would do is adding a fuel pressure gauge visible during the drive. There you can see, if you get enough fuel. 88 jets for a 1050 sounds awfully small to me; find out what were the jets out of the box and use them for starters. Check the valvespring pressures, and check for coil bind in the springs, also check that all valves have the supposed lift and that the vlve clearances are ok. If you have had to adjust them a lot, you have a problem. Have you measured the CR, or is there just 11.5:1 pistons? Is the cam timing correct?
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#15
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Heres a simple test to see if your compression doesnt match your cam,add 18" tork tubes,if your 60ft or ets improve its a sure sign they DONT match,you already stated that a 750 ran as hard as a 1050,this is a good indication they dont,also generally speaking a 2.125" header tube is too big,also most 2.125 tube headers are 38-40" long which is also too long,this allows the backpressure to escape so fast that its actually pulling some of the intake charge right out the exhaust,most likely youll see a .4 et reduction.Also a 264* cam should pull to 7400 or so,you might need to degree it.Also you might put that fat ass car on diet......PRO....
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#16
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Personally, I don't think the cam or the carb is too big. The car should sixty better than that, even at that weight you have enough power to go low 1.40s if the car works well. I would look into a converter problem. I think you need more pump than a Holley "blue". Even if you have good pressure at the finish, this pump does not have enough volume to supply adaquete fuel at higher RPM, this could be why the mph is down and also why the Dominator and 750 ran the same.
Monte Smith ------------------ SURGEON GENERALS WARNINGrag Racing is highly addictive, and may impair your ability to make rational decisions. |
#17
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The Holley blue pump does not produce enough volume for a 440. And the Holley blue regulator is worse. They might work for 1/8 mile but not 1/4.
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