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Not to Hijack the OP's thread but. Has anyone ever rigged up a temporary vacuum gauge using a carb spacer as a source? I'm not poking holes in my new Hogan's intake. Thanks
 

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Not to Hijack the OP's thread but. Has anyone ever rigged up a temporary vacuum gauge using a carb spacer as a source? I'm not poking holes in my new Hogan's intake. Thanks
I have not, but it should not be a problem to dill and tap a hole for some type of nipple.
 

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Discussion Starter #23
Quick Fuel sells a Brawler Series 850 that is less expensive. It is a street/strip version. Has a electric choke, which of course can be removed, mechanical secondaries, and a lot of good features for the price. $400 range. PM me if you want details.
Do you think an 850 or 950 would be better? If the engine is pulling 2” of vacuum, how many more cfm would it need to bring it down to say 1”? I would hate to buy an 850 just to test it and find i should have went bigger.

Looking at both the Q race series and the race series from the Brawler line, spec wise they seem very similar, do you think the Q series is $300 better? I’m leaning towards the Q series but $900 is nice chunk of change and I’ve been thinking about building/buying a g force trans.

I did mostly fix the issue with the engine braking up, I flipped the stock pink accel pump cam and it almost cured it. I wentand picked up a pack of the cams and just installed the blue cam but rain has been sprinkling on and off so I can’t test that one yet.
 

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A 750 would probably be fine with mech secondaries and without the airhorn choke. Otherwise try an 850 if you're running a choke

A 347" with AFR 185's at 7,000 doesn't need anything bigger than an 850.

Vac over 1.5" is restrictive, but it's not the end of the world. My 565 pulls 1.9" of Vac thru a 1,050. ..Still makes 950 hp at 7,000.
 

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....
Duplicate post
 

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See post #1 and post #46 in the thread below



Sorry the vac gauge wasn't hooked up.
 

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A 750 would probably be fine with mech secondaries and without the airhorn choke. Otherwise try an 850 if you're running a choke

A 347" with AFR 185's at 7,000 doesn't need anything bigger than an 850.

Vac over 1.5" is restrictive, but it's not the end of the world. My 565 pulls 1.9" of Vac thru a 1,050. ..Still makes 950 hp at 7,000.
My 532 picked up .25 and 5 mph going from 1.9" @ 8000 rpm down to .3"... That's around 80 HP or so.... But it is a healthy engine I spin to 8500 rpm....
The OP likely would never see near that, maybe 15 HP on his milder engine.
 

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Long Live The King
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Not to Hijack the OP's thread but. Has anyone ever rigged up a temporary vacuum gauge using a carb spacer as a source? I'm not poking holes in my new Hogan's intake. Thanks
yes you can. 3/8" nipple
 

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Discussion Starter #30
It's likely the carb needs some major work to get the secondaries to open. Try a classic Holley 750 DP carb, 4779.
I was able to adjust the secondaries and I got the vacuum to around 1.5-2, it drops to that as soon as I go wide open.

we’re you recommending the Holley 750 based on the original post or even still after getting the vacuum down, you would still recommend it?
 

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See post #1 and post #46 in the thread below



Sorry the vac gauge wasn't hooked up.
What size carb did you end up with on that 347?
 

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IF memory serves, the 750 Demon with the Holley 850 base plate flows about 810.
 

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My 532 picked up .25 and 5 mph going from 1.9" @ 8000 rpm down to .3"... That's around 80 HP or so.... But it is a healthy engine I spin to 8500 rpm....
The OP likely would never see near that, maybe 15 HP on his milder engine.
What size carb did you start with and what size brought it down to .3 ? thanks
 

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OP, be aware that not all advertised cfm ratings are the same or legit for 4150 style carbs, depending on manufacturer. Holley 850, demon 850 will flow near the same as a holley 950. Holley 950 typically flows about 830. Quick fuel carbs are usually pretty accurate to their rating. If yours is mostly race application, go with the shaved choke horn quick fuel 850 with mechanical secondaries. Vacuum secondarys and chokes are for cars the get driven year round mostly on the street and in cold weather. If your spending close to a grand anyway, get with a reputable carb builder, tell them what your combo is and have them build what you need, that way it will be spot on or close and you won't have to dick with it much or at all once you get it. Davinci, BLP, pro systems.....
 
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