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Demon/Holley carb question


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I recently bought a Demon 850 to replace my holley 650hp, which I thought was too small to do what I needed it to do. The 850 runs better, but I dislike the design. Jet changes are a bitch due to the allen head bolts that are countersunk into the casting. With the holley, I crack the bolts loose and spin them out with my fingers....the demon requires a tool to be used to remove the bolts all the way. Does anyone know if holley bowls will work on a demon carb? I suppose I could just get longer bolts and make some spacers, but I've got a bunch of holley carbs laying around. I don't see why they won't work...but I haven't tried it yet. Maybe someone else has? The only things I'm worried about are the accel pump circuits and linkages.

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I've got a Race Demon on the shelf at the house and IIRC the bowls are a different shape altogether than the Holley they are more round and the bowl is actually a semi circle where as a Holley is a square shape, sorry I can't tell you for sure but I'll look tonight when I go home. My Demon got shelved when I bought one of theese best money I ever spent the response is almost as good as fuel injection and it never needs to be adjusted or jetted.

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_743833_-1_10271

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I've got a Race Demon on the shelf at the house and IIRC the bowls are a different shape altogether than the Holley they are more round and the bowl is actually a semi circle where as a Holley is a square shape, sorry I can't tell you for sure but I'll look tonight when I go home. My Demon got shelved when I bought one of theese best money I ever spent the response is almost as good as fuel injection and it never needs to be adjusted or jetted.

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_743833_-1_10271

 

How's your mileage with the Predator? I knew a guy a few years ago who tried one, and IIRC, his was thirsty.:-(

 

 

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Mine only gets about 7mpg but it's on a 427 race-only big block in a full bodied '71 Nova so it really can't be taken as any indication. I do have a friend that runs one on a 383 in his '80 Cutlass and it gets 16-18 sometimes as high as 20 if he stays out of the throttle so it's not bad.

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I recently bought a Demon 850 to replace my holley 650hp, which I thought was too small to do what I needed it to do. The 850 runs better, but I dislike the design. Jet changes are a bitch due to the allen head bolts that are countersunk into the casting. With the holley, I crack the bolts loose and spin them out with my fingers....the demon requires a tool to be used to remove the bolts all the way. Does anyone know if holley bowls will work on a demon carb? I suppose I could just get longer bolts and make some spacers, but I've got a bunch of holley carbs laying around. I don't see why they won't work...but I haven't tried it yet. Maybe someone else has? The only things I'm worried about are the accel pump circuits and linkages.

 

I actually liked the allen heads on my Demon. Easy to keep a small allen wrench in the ash tray and access is better on the back bowls than using a screw driver. My Holley HP needs a small socket hex rather than screw slots. PITA. Maybe my Demon was a bit more broken in, but once a little was exposed past the casting I could spin them out by running my index finger across them, as fast or faster than the holley.

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