Anyone use a Demon Carb

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Yup, run a speed demon 750 DP'r. Love it especially the sight glasses on the side of the bowls. Pulled it out of the box, jetted primary down one size and haven't touched it in over a year.

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Yes, They are very good at what they do.

But...

I've found issues with metal shavings and flash in the metering blocks, and they can be set very close to perfect. So close in fact that around me, if I set one perfect in the mid day heat, when the sun goes down, the tune will be off. And then I change it to be perfect in the cooler air, it runs way different when it gets hot. I havent messed with air bleed sizes yet on the troublesome one, I'll do that when this particular car returns this spring. I'm thinking the main bleeds are too large. This is an Indy supplied 750. Others I've seen have had metal issues, but ran decently after "cleaning them out".
 
I ran a Mighty Demon 650 on my last 306, and had nothing but good luck with it. It was a little finicky as Moper suggests, but easy to tune. I didn't have to touch the air bleeds, although I did go to a smaller set and didn't like the results, so I went back.
 
I purchased a 725 Road Demon last year and could never get the transition circuit sorted out (spent most of the summer fiddling with it until I put the Holley back on). The car ran like crap between 1000-1800 rpm. BG's tech support was less than helpful when I called them and basically told me I purchased the wrong carb and said to get a 650 Speed Demon. The only difference other than jet sizes between the 725 and 650 is the venturi size in the main body I asked about purchasing a 650 main body and basically was blown off.

IMHO, I would stick with Holley. You can purchase basically any part you need either directly from Holley or through the many aftermarket suppliers, plus there are a bunch of outfits that can provide support or setup of a carb for you. Even thought the Demon carb is patterned after a Holley there is enough differences that only jets, gaskets, PV's are interchangeable.
 
thats great advise....next question is .....which demon carb (cfm) whould you all suggest for the 390 hp 360 create moter?
 
Demon carbs can be very troublesome my last one took forever to get properly tuned,thank goodness i sold the car with it....i'm running a Quick Fuel technology 850 on my stroker presently,best carb i've EVER used ran consistenly great all last season,with nothing more then taking it out of the box and adjusting idle speed........
 
UPDATE!!
As of this morning, my customer with the problem carb guy said "I'm tired of this carb. Look into EFI for it."

lol.
 
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