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Author
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Topic: 351c with 1000HP carb
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70coupe
Gearhead Posts: 483
From: Toronto,Ontario,Canada
Registered: Aug 2000
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posted 05-05-2002 11:18 PM
  
I was running a 750dp last year on my 351c 4v closed chamber head motor and ran a best of 12.37@110. I tried a brand new holley 1000HP carb and ran a best of 12.87@105. Checked the plugs and they seemed to be dry and clean. Whats the deal? I figured if the 1000cfm carb was too much the plugs would foul. Is it possible with the larger bores on the 1000 that the signal was reduced therefore causing the lack of power? The et was down .5 as well as 5mph. 60fts were close with both but the 750 was better.
Any input appreciated.
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Fordwiser
Gearhead Posts: 442
From: Metamora, Illinois
Registered: Dec 2000
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posted 05-05-2002 11:48 PM
Maybe the cam is not big enough to flow that much volume, also may need more gear and stall speed to get the velocity up.
Roger
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70coupe
Gearhead Posts: 483
From: Toronto,Ontario,Canada
Registered: Aug 2000
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posted 05-06-2002 10:27 AM
I have a 10" 5000 converter and the cam is a crane solid 570/590 lift and 246/256 duration. Gears might be a little low 411's but the stall should put me in the power range.
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fastbackRb
Gearhead Posts: 100
From: Columbus,Ga.
Registered: May 2002
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posted 05-06-2002 10:34 PM
I had simalar problems with mine when I went to the 2 1050's .I tried jetting up an d wound up with 110 jets and still was lean on the big end. It took alot of time but finally got it better. Your 1000hp has adjustable air bleeds (they are up where the airhorn would normally be)the look like small jets. One is for the idle circuit and the other is for the main metering circuit.With the size of the venturi the carb s not responding or reading the signal from the small cubic inch engine.You will have to go smaller on the air bleeds to get it to respond.(it is like sucking water thru a straw no you get a mouthful, a small hole and you get a little air with your water,a big hole and you get a lot of air and alittle water.)The big carbs are set up for big inch engines. Go back tto the paper work you got with carb and it should tell you which air bleed is for which circuit and start by going down 1 size at a time make a pass and read the plugs or if you started picking back up in mph keep getting smaller on them until you slow down again back up and try changing jets. I would not change the idle circuit onesover 2 sizes because it will get rich real quick and foul the plugs or just be hard to crank.Sorry for being long winded and any misspelled words but hope it helps. Rudy  5.80's@117mph 70 fastback
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n2oMike
Gearhead Posts: 2831
From: Spencer, WV
Registered: Jan 2001
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posted 05-06-2002 11:48 PM
I recently read two dyno articles, and both stated that if a carburetor starts going rich on the top end, then increasing the size of the main air bleed would help. One dyno test was with a dual four tunnel ram Mopar, the other a 406 Chevy. By the way, where do you get those little jets, and how much are they? A friend has a carb with interchangable air bleeds, and would like to play with them... Thanks! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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fastbackRb
Gearhead Posts: 100
From: Columbus,Ga.
Registered: May 2002
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posted 05-07-2002 12:22 AM
quote:
Originally posted by n2oMike:
I recently read two dyno articles, and both stated that if a carburetor starts going rich on the top end, then increasing the size of the main air bleed would help. One dyno test was with a dual four tunnel ram Mopar, the other a 406 Chevy. By the way, where do you get those little jets, and how much are they? A friend has a carb with interchangable air bleeds, and would like to play with them... Thanks!
Don't know price for singles but assortment for ome carb was about 175 shiping and handleing From BCI in Atlanta Jegsand summit about the same.You are right if it richens up go bigger or rejet with smaller jetson the metering plate.But 70coupe's problem is just the oppisit.He needs smaller air bleeds .(By changing jetts in the metering plate you kind of split between the sizes of air bleeds one to small the next to big) Rudy
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70coupe
Gearhead Posts: 483
From: Toronto,Ontario,Canada
Registered: Aug 2000
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posted 05-07-2002 01:12 PM
The current air bleeds are 75's on the outside and 25's on the inside. I will see if I can come up with some 25 or 50's to change the outside ones.
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fastbackRb
Gearhead Posts: 100
From: Columbus,Ga.
Registered: May 2002
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posted 05-07-2002 10:39 PM
Hey 70 I would not go that many 75 to 50 is 25 steps would try 73 or 74's. Rudy
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70coupe
Gearhead Posts: 483
From: Toronto,Ontario,Canada
Registered: Aug 2000
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posted 05-10-2002 12:45 PM
Well, I give up on the 1000HP due to the throttle bore size and have now bought a 950HP with the 750 size bores. I will test it out on the May 18,19 weekend. I'll let you know how it works on the cleveland. I was told by several places that this is the perfect carb for my motor(heard that before!)
Brian.
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kid vishus
Gearhead Posts: 6590
From: middle of NC
Registered: Oct 2000
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posted 05-10-2002 12:49 PM
quote:
Originally posted by 70coupe:
Well, I give up on the 1000HP due to the throttle bore size and have now bought a 950HP with the 750 size bores. I will test it out on the May 18,19 weekend. I'll let you know how it works on the cleveland. I was told by several places that this is the perfect carb for my motor(heard that before!)
Brian.
I had a 950HP on my cleveland till I changed it over to alcohol. It worked better than any other gas carb I ever tried. ------------------
Rob
member #773
'69 mustang, 351C, 9.97 @ 133 mph 1/4, 6.27 @ 108 1/8, 1.344 60'
'70 mustang, flintstone power
'93 F150 Lightning 15.33 @ 87 mph, completely stock with 149k miles
'99 Pro Et track champion
'00 Mod ET R-up (with new car) My Photo Page
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fastbackRb
Gearhead Posts: 100
From: Columbus,Ga.
Registered: May 2002
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posted 05-10-2002 10:49 PM
Hey kid tell me more about your cleveland on alcohol.
Rudy
------------------
70 fastback cleveland
69 cougar elimnator b 02
84 droptop 5.0
86 hatchback 289
92 explorer
97 f350 dullie
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kid vishus
Gearhead Posts: 6590
From: middle of NC
Registered: Oct 2000
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posted 05-12-2002 10:25 AM
quote:
Originally posted by fastbackRb:
Hey kid tell me more about your cleveland on alcohol.
Rudy
Its a pretty standard build. It's a .030 over 2 bolt main block, cast factory crank that has been turned .020/.020, stock rods that have the normal prep (ARP bolts, full floated wrist pins, polished and shot peened beams) Arias domed pistons, ATI dampner, 4v open chamber heads that I ported that have been cut down to 67 cc combustion chambers, Crower stainless rocker arms, lite weight 3/8" pushrods,
strip dominator intake I did a little work to with an old BG modified 750 alcohol carb that now flows 920 cfm on top, and full MSD ignition. I have run a solid and a roller cam, they are pretty similar and run about the same (fastest pass was with the solid actually). The solid is from Crower, 266 int, 277 exh @ .050, 107 LSA, 103 int center, with .628/.625 lift. The roller is from Lunati, 264 int, 272 exh @ .050, 108 LSA, 104 int center, with .650/.650 lift. I shift them both at 7400 out of low, 7000 out of second, and go thru the lights around 7200 - 7300 rpm.
I hope that was what you were wanting to know.
I have a good convertor, and thats a big part of where my ET comes from. Plus the car is light, and that helps too.
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fastbackRb
Gearhead Posts: 100
From: Columbus,Ga.
Registered: May 2002
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posted 05-13-2002 11:48 PM
quote:
Originally posted by kid vishus:
Its a pretty standard build. It's a .030 over 2 bolt main block, cast factory crank that has been turned .020/.020, stock rods that have the normal prep (ARP bolts, full floated wrist pins, polished and shot peened beams) Arias domed pistons, ATI dampner, 4v open chamber heads that I ported that have been cut down to 67 cc combustion chambers, Crower stainless rocker arms, lite weight 3/8" pushrods,
strip dominator intake I did a little work to with an old BG modified 750 alcohol carb that now flows 920 cfm on top, and full MSD ignition. I have run a solid and a roller cam, they are pretty similar and run about the same (fastest pass was with the solid actually). The solid is from Crower, 266 int, 277 exh @ .050, 107 LSA, 103 int center, with .628/.625 lift. The roller is from Lunati, 264 int, 272 exh @ .050, 108 LSA, 104 int center, with .650/.650 lift. I shift them both at 7400 out of low, 7000 out of second, and go thru the lights around 7200 - 7300 rpm.
I hope that was what you were wanting to know.
I have a good convertor, and thats a big part of where my ET comes from. Plus the car is light, and that helps too.
Yea pretty much. Seen pics of the car looks good to. How lite and looks like maybe 14s on back? Good luck with it.. Rudy
[This message has been edited by fastbackRb (edited 05-13-2002).]
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kid vishus
Gearhead Posts: 6590
From: middle of NC
Registered: Oct 2000
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posted 05-14-2002 05:33 AM
Thanks
And I do tend to do fairly well with it  Yep, 14x32's on the back. Ladder bars with coilovers. It weighs 2835 lbs with me and some ballast in it. Without any ballast, and wihout the Borla's, it weighs 2710 lbs with me in it. That's pretty ligth considering the only piece of fiberglass on the car is the hood.
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