Dominater problems

Old 06-18-2009, 11:10 PM
  #1  
southerland
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Default Dominater problems

Why would a 750 dominater be loading up on a 505ci big block. I wanted a smaller dominater to be a little more street friendly but this carb is loading up getting a very rich fuel smell and exhaust smoke. Do I need to drill the butterflys to get a better idle? Would it be a power valve problem? All jets are factory jets 88s on all four corners, and bleeds are factory 73 on idle and 36 on high speed.
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Old 06-19-2009, 07:04 AM
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jmarksdragster
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What model #on the carb? The 80176 750 Dominator came with 70's for jets. 88 would be REAL fat unless the carb has been modified, replacing the large skirted boosters with straight ones will add a bunch of CFM and require more fuel. Here is the Holley site with list #'s and specs.

http://www.holley.com/data/TechServi...%20Listing.pdf


Air bleed specs.

http://www.holley.com/data/TechServi...ifications.pdf
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Old 06-19-2009, 07:18 AM
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ashbros
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It may be I am not well versed with the tuning of carbs with power valves, but I always jerk them out of every carb I use. Seems they are always blowing out.

jm $0.02
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Old 06-19-2009, 07:20 AM
  #4  
dparker
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Default Re: Dominater problems

Originally Posted by southerland
Why would a 750 dominater be loading up on a 505ci big block. I wanted a smaller dominater to be a little more street friendly but this carb is loading up getting a very rich fuel smell and exhaust smoke. Do I need to drill the butterflys to get a better idle? Would it be a power valve problem? All jets are factory jets 88s on all four corners, and bleeds are factory 73 on idle and 36 on high speed.
If you have powervalves the 88's are way to big. That would be like running 98s without the powervalves. The powervalves add 8 to 10 jet sizes with the extra fuel they help deliver. NOW IF you powervalves go down to at 78 to 80 jets and try it. I usually always block the powervalves but if your running alot on the street, you may want to try to keep them.
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Old 06-19-2009, 10:45 PM
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southerland
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Default 750 dominator

The Part# is 80186-1 it is a two circuit carb. The idle bleeds are 73s and the high bleeds are 36s. And yes I looked and the stock jets are 70s. But does the main and secondary jets really have anything to do with the idle? Might be a stupid question but Im trying to learn how to really tune a holley. Holley says not to touch the air bleeds but we all know weve got to do what we must sometimes. also holley says that you must check your vacum to be able to tell what power valves to run. I know that there isnt much vacum to my motor. Thanks!!!!!!!!
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Old 06-20-2009, 03:56 PM
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Main jet should not affect the idle unless you have another issue, leakage in the gasket between channels, air bleeds plugged. Leakage around or through the power valve can also be an issue. My suggestion is a good cleaning and jet close to stock. What is the rest of the combination and what timing curve is in it?
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Old 06-20-2009, 11:48 PM
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southerland
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Default dominater

Combination, do you mean carb? I dont really know.I need to tear it down. I would think that it all is factory. but he was raising jet sizes, it might have larger pump size and power valves might have been changed. It seems he was trying to get this 750 to perform on the 505ci motor instead of just getting a larger carb. Holley says this motor needs an 1150 to perform well at the track or a 950 on street. I feel like the 750 Dominater would be a good carb on street and strip if I can just get it tuned correctly. If your talking about motor, the 505 has a HRC crank and h-Beam rods, SRP forged flat tops with 2 valve relief. Dart pro1 heads 325cc intake port and 121 chamber volume 2.30/1.88 valves, Dart intake ported to heads. Solid roller cam around 260/270 @ .50 and 740 gross lift. All MSD ignition, 6al box, autolite race plugs(and they seem to be holding up godbless em) I need to get a crank case evac running it is a brand new engine but it seems to be pushing a little oil by, that might be some of my problems, maybe??????? as far as timing Ive got the distributer set to be at full timing at around 2500 and im running 34 total timing. And thats it in a nutshell.
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Old 06-21-2009, 04:37 PM
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You state you have 34 total timing at 2500, how about at idle? A few degrees of timing makes a huge difference in how a engine idles. I would prolly install an advance curve kit with the black bushing and light springs.
You will be amazed at how much difference this makes. JMHO
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Old 06-21-2009, 09:38 PM
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Are you sure your floats are not set too high??
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Old 06-22-2009, 08:12 PM
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southerland
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Default dominater

I checked the floats the old fashion way I took the side screws out with the carb on motor and the fuel level was just up to the threads, none was over flowing. One thing I noticed today was the idle air bleeds in the carb was 71's. I had some in a 750 hp that were 75's and I switched them out and this some difference. I know that they are supposed to be 73's but thats all I had lying around. Still smell alot of fuel though, maybe thats the way its just gonna be. I think Im still gonna take this carb down and give it a good cleaning and maybe try smaller jets. I dont think I need to go back to 70's though that seems kinda small for a 505. I did put the 750 hp on for the Hot Rod reunion here in Bowling Green this past weekend and as far as street driving it loved it, but you could tell if you got in the throttle is just wasnt enough. Maybe a stupid question but whats the difference between a 4150 750 hp and a 750 dominater, should there be that big of a difference????
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