Anybody have experience with Demons. 750 double pumper’s that is.

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PG Duster

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I have a 750 HP carburetor vacuum secondary on my 360 magnum Duster. I have a friend that has a brand new in the box still in a plastic 750 double pumper Damon carburetor, what do you guys think about demon carburetors versus a Holley? Your input would be appreciated. I’ve always used Holley or Carter carburetors on my mopars. I talked to C J carburetors in Southern California that does a lot of super stock and stock illuminator carbs and he replied to me about seven years ago that demon carburetors have their own demons he prefers a Holley.

Almost for got to give this information. 1974 Plymouth Duster, 360 magnum engine, 9.1 cr, ported EQ cylinder heads with 2.02 intake valves, mild hydraulic roller cam shaft, I don’t have the cam specs, with Edelbrock rpm airgap intake, Holley HP 750 vs carburetor, MSD ignition system, aluminum radiator, 2 1/2 inch exhaust system with Flowmaster mufflers, headers, and a built 727 trans with a 9.5” 3600 stall built by Dice Performance Converters, B&M SFI flex plate, B&M pro ratchet shifter, line lock, Calvert Caltrac traction Bars and split mono rear leaf springs and Calvert 9 way adjustable rear shocks and Yukon racing axles, a 489 3rd member housing, 8 3/4 sure grip rear end with 3:91 gears in it. 275/60 15 Mickey Thompson drag radials rear tires. And almost finished installing nitrous hundred shot system on a car.



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This is the carburetor I have on it now.

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For what its worth......
I bought a gold claw RS (prehistoric demon) from a friend, off of his 408 Windsor, and plunked it on my 406 Chevy. I don't think I even changed the jets, or had the bowls off. I thought it had the 850 sleeves, turned out to have 770cfm sleeves. Ran good enough in my car to get to 6.30s at Irwindale.
I have heard that there are many quality control complaints about the latest versions of the holley copy demons. I know nothing about the new thermoquad-like ones.
To be honest? I don't think it will improve any on your QFT.
 
For what its worth......
I bought a gold claw RS (prehistoric demon) from a friend, off of his 408 Windsor, and plunked it on my 406 Chevy. I don't think I even changed the jets, or had the bowls off. I thought it had the 850 sleeves, turned out to have 770cfm sleeves. Ran good enough in my car to get to 6.30s at Irwindale.
I have heard that there are many quality control complaints about the latest versions of the holley copy demons. I know nothing about the new thermoquad-like ones.
To be honest? I don't think it will improve any on your QFT.


Thank you for that Information, and I have always used a vacuum secondary on a dual plane intake and a double pumper on single plane Intake manifold. I just have to connect up my bottle heater and fuel pressure switch on the Nitrous, and it will be test time.
 
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I don't think the Demon carb will make much if any difference over your QFT. I sold a ton of the original Barry Grant modified Holley's in the 90's and those carbs were incredible. I sold quite a few of the original Barry Grant Demon carbs back in the late 90's and early 2000's and they were okay carbs, at least the equal of a Holley. The original Demons had more quality control issues than Holley, other than that they ran well, but were not exceptional carburetors like the late 80's early 90's Barry Grant modified Holley's.
 
I don't think the Demon carb will make much if any difference over your QFT. I sold a ton of the original Barry Grant modified Holley's in the 90's and those carbs were incredible. I sold quite a few of the original Barry Grant Demon carbs back in the late 90's and early 2000's and they were okay carbs, at least the equal of a Holley. The original Demons had more quality control issues than Holley, other than that they ran well, but were not exceptional carburetors like the late 80's early 90's Barry Grant modified Holley's.


Thank you for sharing your carb. experience. Greatly appreciated.
 
I had excellent success with the Original Demon cars 750/850/King
and still run them on several cars!
The newer ones the last number of years have not been worth sh*t!!
 
I had excellent success with the Original Demon cars 750/850/King
and still run them on several cars!
The newer ones the last number of years have not been worth sh*t!!

Thanks GTX John, I haven’t seen you in over 30 years, remember me I bought that turn key 1969 440 6 pack c/stocker with the Landbeck engine in it from you. This is Gerald, we used to hangout at the street races in LA many years ago.
 
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Yes Sir I do = you were a buddy of mine.
If you wish text me your # and I will buy you lunch or
dinner next time I am down that way?
That car was the national record holder in NHRA for quite
a while.
How old is that Demon carb?
 
Yes Sir I do = you were a buddy of mine.
If you wish text me your # and I will buy you lunch or
dinner next time I am down that way?
That car was the national record holder in NHRA for quite
a while.
How old is that Demon carb?


That sounds good, I will pm you my number. The carb is about 20 years old. New in box, never used.

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View attachment 1715976722

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Yes Sir I do = you were a buddy of mine.
If you wish text me your # and I will buy you lunch or
dinner next time I am down that way?
That car was the national record holder in NHRA for quite
a while.
How old is that Demon carb?


About 20 years old. This is the car I have now.

584D08BC-D3A0-455E-9DFD-9A692B66DB96.png
 
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I have used two of the Holley Demons [ black plastic centre ]. One a 625 on a Chebby, worked ok. Other was a 750 on a 400 Pontiac, could never eradicate the bog when the secs opened. Owner rang Holley, tried all the 'fixes'. Original QJ went back on, no bog.
 
I have used two of the Holley Demons [ black plastic centre ]. One a 625 on a Chebby, worked ok. Other was a 750 on a 400 Pontiac, could never eradicate the bog when the secs opened. Owner rang Holley, tried all the 'fixes'. Original QJ went back on, no bog.

thank you for sharing that, it seems like only the old Berry Grant carburetors we’re good.
 
I like the Demon's. That 750 is a good carb but to big for your setup IMO OOTB. Any carb needs to be dialed in to optimize a combo. Search speedtalk for info on tuning it.
Put a vacuum gauge on the car and video the readings at the track with your current setup. Also the paperclip on the sec vacuum rod trick will let you know if the sec open fully.
A smaller tire will help you more than a carb especially running 1/8 mile.
Demon specs:
 

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I like the Demon's. That 750 is a good carb but to big for your setup IMO OOTB. Any carb needs to be dialed in to optimize a combo. Search speedtalk for info on tuning it.
Put a vacuum gauge on the car and video the readings at the track with your current setup. Also the paperclip on the sec vacuum rod trick will let you know if the sec open fully.
A smaller tire will help you more than a carb especially running 1/8 mile.
Demon specs:

thank you, I will use your suggestions. What size tires?
 
[QUOTE="GTX JOHN, post: 1974037496, member:
The newer ones the last number of years have not been worth sh*t!![/QUOTE]
Almost like everything lately?
 
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