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Discussion Starter #1
I've searched and kinda know what I need to adjust but would like some opinions.

500 ci BBC, 13.5 comp, 1050 dominator, supposed to be opened up to 1125 cfm. This carb came with engine . I have upgraded and made changes to the engine but never adjusted the carb.

Yellow cams #1 hole, 50cc accelerator pumps, started with 35 front nozzle, 31 rear nozzle. Has both power valves. 98 jets squared with extensions. This year I rebuilt it and fucked up the rear accelerator diapham, fixed that and still has the bog. I have adjusted the pump actuators.

It's in a straight line mud race truck. No trans brake. Usually I bring the revs up till I can barely hold it with the brakes then left go of the brakes and put it to the floor and start shifting.


Currently I have changed the nozzles to 45 front and 40 rear. Still has the bog, it only got slightly better.

I believe the yellow cams are the most aggressive, should I go less aggressive? Is that the next step? Should the nozzles be all the same size.

Let me Know If ya need more engine info .
 

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Discussion Starter #3
Just change the rear jets? After getting rid of the rear pv? I just bought pv plugs today in case that was the way to go. Have to get jets.
 

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Needs at least 35 nozzle on both ends, Better yet put 37's on there. 31 is definitely to small for Dominator. I think you will cure your stumble with the bigger Nozzles, go to 40 if needed.
 

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Discussion Starter #6
I already put 45 in front and 40 in the rear. The bog got a little better.
 

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Try to see how far the throttle is open on the line. A lot of your pump shot may be gone. May be able to tighten the bolts on the pump arms and get some of it back.
 

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Discussion Starter #8
if i wack open the throttle the bog is there. if i come up on the convertor a bit it doesn't bog when i go wide open.


i'm trying to get rid of the bog to get the tires to break loose faster.
 

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Where are your idle A/F screws adjusted to? Try turning them out 1/4-1/2 turn more, counterclockwise, and see if the bog gets better. If so, it is lean at idle.

No power valve in rear and maybe none in front.
 

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I never ran powervalves in my dominators. I found that they caused it to go rich and stumble. My last one was done by Dale Cubic and he built it the same way.
 

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Discussion Starter #14 (Edited)
Tried putting the yellow cams in the #2 hole. The bog got way
way worse. Yes I adjusted the levers with the change.

The kit I bought only has yellow cams, so I can't change those.

I'm trying to adjust with what I have for now.
 

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Discussion Starter #15
I adjusted the air screws 3/4 a turn out. Seemed to make it a little better.
 

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Who opened the carb "up" as you put it??
If they bored the Venturi open and didn't know what they were doing, it's likely trash can material....
Do the venturi's have a long machined area that's flat inline with the boosters??
Post a pictured of a Venturi.
 

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Best thing to do is buy a cam kit and test out the primary Accelerator cams, make sure the cam is making good contact with the little metal tab so that as soon as u touch the throttle fuel squirts out , u may even need to tweak the tab a little to make better contact ,if there is any delay in the squirt U need to take up the slack .as for pump cams I would try red,brown,orange,blue or white on the fronts , secondaries usually like the pink cam . It’s really trial and error but ur solution lies in the right pump cam.
 

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Discussion Starter #18
Rcm- when I bought the engine years ago, that was the info I was given. It's a 1050 flowed to 1125, never asked anything more about it.

68fastback- I bought the Holley pump kit, for the 50cc pumps it only came with 2 cams, yellow and white and I only got 1 white can. The carb I have has a bigger shaft where the cams fit into and the other cams won't fit on. When I adjust the arms that ride on the cams , I get a squirt instantly.

Last thing I did today before the rain was try 45 nozzles front and rear with the yellow cams. The bog seems a little better but still there. Nobody local has the jets I need to block off the power valves. Have to order a kit.

If I rev it a bit to 2k, them wack it open it doesn't bog, but from 1500rpm it bogs.
 

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How much HP this thing make??
Did you ever run it on another engine and it worked???
What intake??
What's the timing at?
A lot of carb spacer??
What fuel psi??
Where are the float levels at ?
You have any idea what idle air bleeds in it??
 

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Discussion Starter #20 (Edited)
Approx 850hp.
Owned and been running this engine/carb combo for 5-6 years. This year it got totally fresh heads, new bearings in the bottom end.
Dart square port intake.
Barry grant modified carb.
38 degrees of timing locked in.
1" of carb spacer
8 psi fuel pressure.
Just checked the floats, fuel just barely comes out the holes while running.
No idea on air bleeds. Didn't write those down when I had it apart.

I rebuild it every year. This year it started the bog, maybe I never noticed it as much, cause I wanted to start taking off from and idle unlike most times I bring it up against the convertor.

The only thing I haven't tried is going back to the way it has always been. This year I took a little bit of slack out of the cam arm to the accelerator arm. Originally it had about a 1/16" gap. I tightened it up to just touching and here we are. All because I wanted to see if I could gain anything.
 
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