Dominator Carbs

Guest · Post by **Guest** » Sat Sep 04, 04 9:17 pm

Anyone know how the CFM on a 750 Dommy is set - from looking around it looks the the primary and secondary venturi and throttle bore are the same size on a 750 as a 1050.
Ive changed the spec again - its a monthly thing - and it now looks like I will be spinning the engine higher than the 750 (which supposedly can flow to 800) can handle.
Only problem is I bought a 'baby' dominator a month or so ago - thinking this would fit my planned engine OK - which is not now the case.
I have noticed that the annular boosters are HUGE and take up most of the venturi - so is this how its been 'downsized' CFM wise and is it as simple as getting a set of 1050 boosters http://www.barrygrant.com/bgfuel/default.aspx?page=69
Damn this engine building lark - driving me round the twist 8)
Cheers
Iain

Guest · Post by **Guest** » Mon Sep 06, 04 10:25 pm

Just in case anyone is wondering WTF im on about

Took a pic tonight, the umbrella arrowed is the area that I think is restricting flow.
The pictures from the Barry Grant site dont show these - so im therefore taking an educated guess that by removing mine and replacing with the new ones my CFM will increase (though needing re-jetting)
Any thoughts?

Guy · Post by **Guy** » Tue Sep 07, 04 5:11 am

Ian can you remind what size is your motor and what sort of rpm you will be taking it to ?

Before changing the annular boosters check that there are no differences in the internal fuel circuits you may just end up putting in more air than they can supply fuel. I used a 750 dommy on my Nova and that reved freely to 9000 mind you it was a 331 sbc.

Guest · Post by **Guest** » Tue Sep 07, 04 8:49 am

Guy,
It looks like I have finally settled on a 427+30, spinning to 7000
Would like it to go higher, but my oval ports will run out of air

Also running a solid roller - hence the recent change needed in CFM as I would have been spinning to less RPM with my original plan.
If I can get the heads to flow more - then obviously this will all change again (as in I will Bananarama! further)!
Dont need 1050 CFM - more along the lines of 850/900.
According to the Holley site - the only differences between then (apart from the boosters) is the jetting - everything else matches between the 750 & 1050
Thanks for your help - appreciated.
P.S. dont really want to sell this set up - as I have lost enough money by being indesivice and selling the original induction system

Blue · Post by **Blue** » Tue Sep 07, 04 7:42 pm

Hmm,I'm sure I read somewhere that changing the boosters needs a special tool and is not the sort of thing us amateurs should be messing with! I don't know if that is the only difference either! If you decide to get rid of the carb let me know, I'm thinking about getting one myself...

Guest · Post by **Guest** » Tue Sep 07, 04 8:10 pm

Blue wrote:Hmm,I'm sure I read somewhere that changing the boosters needs a special tool and is not the sort of thing us amateurs should be messing with!

Yup - I have head the same though im not sure what the tool actually does

I had intended to pass the work out to either Peter Knight or ICE as it 'should' be less than an hours work - popping 4 boosters and replacing with new (I would have though)
If I do sell - I will let you know (more money lost - and this cost a small fortune as its never been run 8) ) so will explore this avenue first

Mick · Post by **Mick** » Wed Sep 08, 04 9:59 pm

Matthew Wright's 440 escort has got a 550 lift solid cam and he runs a 1150 dominator and claims he has jetted it bigger.
A lot of people i have spoken to reckon Mopars love big carbs

Kev · Post by **Kev** » Wed Sep 08, 04 10:50 pm

Hey Mick, were you talking to the carb salesman??

Guest · Post by **Guest** » Wed Sep 08, 04 11:35 pm

Mick wrote:Matthew Wright's 440 escort has got a 550 lift solid cam and he runs a 1150 dominator and claims he has jetted it bigger.
A lot of people i have spoken to reckon Mopars love big carbs

only a 550 lift..... oops, this one is a tad higher

though if I dont go with this cam - the lift will be reduced to around .680'ish
One of these days im going to decide on a spec and stick with it, otherwise its never going to get finished

Blue · Post by **Blue** » Thu Sep 09, 04 6:35 pm

I heard that too Mick, I bought an 1150 from Ted, he has run 'em on a few 440's, he swears by 'em!

Dave-R · Post by **Dave-R** » Thu Sep 09, 04 8:59 pm

Yeah a six pack is supposed to be 'too big' in theory for a stock or mild 440. 750cfm or 850cfm is as big as most people go.

A six pack works out to be around 965cfm in 4bbl terms. Even though mine opens manually (not vacuum operated) the engine loves it.

Mick · Post by **Mick** » Thu Sep 09, 04 9:52 pm

I've just put a 1050 on my Dart, it looks absolutely enormous. Sounds nice though.
I think using one on the street could be a bad move i had to pour half a gallon of fuel in just to start it.
If i put the car back on the street i will put a 850 d/p on it.

Blue · Post by **Blue** » Fri Sep 10, 04 4:10 pm

Yep, that's exactly why i'm thinking of getting a 750 dominator, it would be an easy swap at the track.

Mick · Post by **Mick** » Fri Sep 10, 04 10:23 pm

I presume by that, you mean 750 to 1150.
Good idea.

Guest · Post by **Guest** » Wed Sep 15, 04 10:25 pm

Blue wrote:Yep, that's exactly why i'm thinking of getting a 750 dominator, it would be an easy swap at the track.

Blue,
You have a PM that might be a solution to both our problems 8)
Cheers
Iain

(off to count the wifes contractions

)