Demon carbs

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zigs

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I'm looking at a Demon carb. Mighty Demon
850. Its used and I don't usually buy used
but it was only used about 5 times for testing an engine. Don't know anything about Demon
Carbs. I can get it for about half the price of new. Any thoughts on this
 
They are decent carbs. If it's proven work properly and what you need then go for it, as stated they used Holley parts and are currently supported by Holley.
 
I'm looking at a Demon carb. Mighty Demon
850. Its used and I don't usually buy used
but it was only used about 5 times for testing an engine. Don't know anything about Demon
Carbs. I can get it for about half the price of new. Any thoughts on this
I had two of them 10 years ago both of them were junk.
One stuck the throttle shaft the other I never could get to idle.
I know that Summit stopped selling them because of all the returns.
May be a different story now.
I have seen a number of parts being sold as "test only", buyer be ware.
 
I had two of them 10 years ago both of them were junk.
One stuck the throttle shaft the other I never could get to idle.
I know that Summit stopped selling them because of all the returns.
May be a different story now.
I have seen a number of parts being sold as "test only", buyer be ware.
Yea I know had heard pros and cons thats why Im asking but theen again people have problems with Holley and Edelbrock.
 
I'm looking at a Demon carb. Mighty Demon
850. Its used and I don't usually buy used
but it was only used about 5 times for testing an engine. Don't know anything about Demon
Carbs. I can get it for about half the price of new. Any thoughts on this
Depends on your needs:
Assuming no manufacturing goofs - which we've seen in Holleys too...
A BG Mighty Demon would have these things if you're looking for them:
annular boosters
4 corner idle adjustment
idle -eze
threaded for replaceble bleeds and some restrictions.

Advantages would be for
an engine and fuel that prefers a smaller droplet size
an engine with poor vacuum at idle

Disadvantages IMO
almost certainly has high position IFRs
almost certainly has too many emulsion bleeds.

Both of the above can be fixed if you want and are common almost all newer billet carbs anyway.
 
Yea I know had heard pros and cons thats why Im asking but theen again people have problems with Holley and Edelbrock.
True
I myself have had zero issues with Holley and Edelbrock.
I really prefer Quick Fuel carbs, but they are a bit pricey.
 
Depends on your needs:
Assuming no manufacturing goofs - which we've seen in Holleys too...
A BG Mighty Demon would have these things if you're looking for them:
annular boosters
4 corner idle adjustment
idle -eze
threaded for replaceble bleeds and some restrictions.

Advantages would be for
an engine and fuel that prefers a smaller droplet size
an engine with poor vacuum at idle

Disadvantages IMO
almost certainly has high position IFRs
almost certainly has too many emulsion bleeds.

Both of the above can be fixed if you want and are common almost all newer billet carbs anyway.


Just so Zigs knows...all the things Mattax outlined are true. And all are very fixable.

I'm sure Tuner has explained why all the carb gurus decided on way more emulsion than needed, but I don't remember the exact reasons. I do know what happens with all that emulsion. And that's a pretty easy fix.

Moving the IFR's is easy too.

Didn't know it has annular boosters, but in Zig's case that's probably not a bad thing. But we'd need to map the thing out and look what the MAB and IAB's are.

Probably not a bad deal.
 
Just so Zigs knows...all the things Mattax outlined are true. And all are very fixable.

I'm sure Tuner has explained why all the carb gurus decided on way more emulsion than needed, but I don't remember the exact reasons. I do know what happens with all that emulsion. And that's a pretty easy fix.

Moving the IFR's is easy too.

Didn't know it has annular boosters, but in Zig's case that's probably not a bad thing. But we'd need to map the thing out and look what the MAB and IAB's are.

Probably not a bad deal.
Hi Tim was going to give you a call and see what you thought. This is for my 470 in the Dart. I don't think the 750 is cutting it Just doesn't have that pop it should.
Just so you know.
470
Crank- scat-4340 ss
cam Hughes HEH3237BL - .540/547
Pistons Ross 4.371
Edlebrock E street Heads
DP4B Intake
Around 550 HP
323 SG
2800-3000 stall
This is a street car
 
I know you can't go by looks but I thought I would post what I'm looking at.
20200205_143320.jpg


20200205_143308.jpg
 
The problem with the speed demons or the Demon carburetors in general was that there were bits a material from the Machining still left in the bleeds/channels.. and that caused a lot of problems ,usually lean problems. It's all been resolved and the thing you have to look at with a used carburetor is whether or not the throttle shaft is worn out and has play, whether or not the air bleeds have been modified or out of stock spec.

I have one, throttle shaft has play, it caused the idle to change by almost 400 rpm if it shifted just right when the throttle lever was returned to stationary position.
 
The problem with the speed demons or the Demon carburetors in general was that there were bits a material from the Machining still left in the bleeds/channels.. and that caused a lot of problems ,usually lean problems. It's all been resolved and the thing you have to look at with a used carburetor is whether or not the throttle shaft is worn out and has play, whether or not the air bleeds have been modified or out of stock spec.

I have one, throttle shaft has play, it caused the idle to change by almost 400 rpm if it shifted just right when the throttle lever was returned to stationary position.
On this one the owner says it was used about 5 times testing a 454. after it was used it was cleaned and put back in box. Owner said they got a good deal on fuel injection so they went that way.
 
I don't see a thing wrong with that.
Ya I'm thinking even if I get it cheap enough and it needs tweeked , I can run it down to Bonney and Clydes and Jay can service it and still be money ahead. These things run about $800.
then I can put the 750 in the Duster
 
I don't see a thing wrong with that.
Well I backed on the Demon carb. I found a
Holley 850 QF in Vancover. We got to talking and I mentioned I was having engine work done by Toms performance and small world
he said his boss and Tom were good friends.
His company has alot of work done by Tom
 
My dad bought an 850 Demon from Jefferson swap meet here in Wisconsin for i believe $150 bucks around 2009, it sat in a plastic bag until 2014 when put it on my 360 and sucker fired right up! Ran awesome! Then my brother got his 408 and bolted it on man it woke that sucker up! The old 750 ran 12.00s and we put that never opened it and bam 11.89! They work damn good imo.
 
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