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going from 4150 to a dom
I have a sbc 383 which has a holley 4150 reworked which has around 950 cfm the venturis are 1.42 and the base plate is throttle bore is 1.750 and off my dyno sheet and my 1/4 numbers from my 1/8 mile numbers i need a bigger carb
yesterday run example 1/8 time..........6.363 sec 1/4 mile ..........10.12 sec i have a friend that is going to lend me his 1050 dominator and my question is should i run the same jets as i have in smaller carb now and how about air bleeds............thanks in advance guys |
I have always ran a 1050 on all small blocks.
Its a short clip, but in the first portion of this video you'see the truck running on gas using a 1050, As you will see from the exhaust, its not running rich at all, no black puff of smoke http://www.racingjunk.com/video_gallery/60574 You shoud not have a problem at all. This was a flat top 350, good set of heads w/ lots of work and a 5 something lift cam, 2" exhaust. It wasn't much. With the little 142 blower it ran 10.10's. Without the blower it ran 10.70's |
No, the metering is different on the carbs. Is it a factory Holley, if so, what model #?
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Also if your going from a 4150 series carb to a dominator you will need a dominator flanged intake..
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Carb change
Well, here is what I would do, I would put the stock box size jets in it, turn all the idle screws in until they stop and then back them all out 1.5 turns, turn your idle screw out until it is off the throttle, then turn it back in until it just touches it, and turn that in up to 2 turns and that should get you running at idle, thenreadjust from there to your idle you may have had before. Is this a 3 circuit car??? If so, you should have no problem with this carb running. Make sure it has the jet extensions, notched flaot in the back bowl and make sure it is clean inside and out. After you hook it up, make sure you have full throttle fill the bowls up and go like hell :D
x2 on the adapter also. |
The carb i have now is actually a 850 cfm holley with a proform 950 body but my carb guy has reworked the carb so the venturies are bigger but still to small for my car off of numbers the car runs especially in the top end and on the dyno..........i have jet extensions and notched floats and yes when i borrow ny buddys dom 1050 i will check it out ..........not sure if it is a 3 circuit carb or 2 as i don't have it in my hands yet........i also bought a adatper for a dom car b to a 4150 style my intake is............right now i am running front jets #82 with power valve and back #88 with no power valves...........i know i am falling off in the top end and not sure how to jet when i put on the dom carb if i should go bigger or leave the same and the same with the air bleeds..............thanks
here is a video of the car http://www.youtube.com/watch?v=MlNsixubZxs |
I phoned holley today to get their opinion on running a dominator instead of a holley 4150 and going up to a 1050 cfm on my motor..........well this is what he told me that that carb would kill my motor that i need a 4150 750 cfm carb..........well i couldn't argue with him as he was set..........i have my dyno numbers and it is showing in the top end that the car is running out of carb and also from my 1/8 mile times to my 1/4 times there is something wacko...........he then told me that probably my fuel system wasn't delivering enough fuel or i needed more jet............. i can post my dyno numbers
rpm torque hp manvac hg 4900 510 480 .81 5000 516 494 .84 5100 521 509 .93 5200 522 515 .95 5300 525 523 .98 5400 518 531 1.01 5500 516 541 1.05 5600 513 548 1.08 5700 510 553 1.11 5800 507 560 1.15 5900 504 566 1.19 6000 501 572 1.23 6100 496 576 1.27 6200 495 584 1.31 6300 490 587 1.35 6400 484 590 1.37 6500 476 592 1.40 6600 472 594 1.40 6700 466 595 1.41 6800 457 592 1.43 6900 449 590 1.45 7000 441 588 1.47 give me your thoughts guys and thanks in advance |
I would agree with the Holley guy. 1050 is way too big for a 383ci. Too many guys make the mistake of going too big on the carb. I ran a 1050 on my 572ci after finding an 1150 too big. Check your fuel delivery.
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How do you know it's the carb? Might be cam or heads?
I wouldn't run a 950 or 1050 on a 383. Not unless we're talking about 15:1 and a .750 cam with little chief heads. At 8000 RPM and 100% VE, that motor is only going to use 887 CFM at most. At 80% VE, it's only going to need 710 CFM. The 4150 carb you have now is plenty. From 6500 to 7000 the power flattens out and the torque drops. What cam/heads/intake are on it? |
Originally Posted by OneBadGMC
How do you know it's the carb? Might be cam or heads?
I wouldn't run a 950 or 1050 on a 383. Not unless we're talking about 15:1 and a .750 cam with little chief heads. At 8000 RPM and 100% VE, that motor is only going to use 887 CFM at most. At 80% VE, it's only going to need 710 CFM. The 4150 carb you have now is plenty. From 6500 to 7000 the power flattens out and the torque drops. What cam/heads/intake are on it? TS1955 |
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