How well do they run out of the box and how is driveability and mileage? I plan on possible putting a 650 one on a 350 with a mild cam 204-214 with .440/.460 lift with 1.6RR, 9.6to1 comp, and Torquer S/R heads (possibly Fully Ported with bigger valves). So probably a 290-340HP engine depending on the heads (stock or Fully Ported with bigger Valves, $$$Question), would the throttle resonse be decent?Thanks

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305TBI FireBird, Holley Intake and TBI, Headers, Torquer Heads, Gears. Best E.T. 15.08 at 92.5, 0-60 6.45.(Before Heads)Summit cam purchased 204-214, to be installed "soon". And maybe a TPI swap,

 

I have a 750 Speed Demon on my 355 in my Z.Had to tune it out of the box for my motor,jets,squirters,etc.No more than I have had to do on any of my Holleys,but with better results!Now that it is tuned to my motor,throttle response is better than my '86 TPI T/A had(sold it),seriously!!I wont go back to a Holley,too many bad experiences!Have had Edelbrock carbs also,they are a good carb also.Plus the Demon looks bad a** on the motor!Driveability is as good as it can get with my combo,loves to be in the high RPM's.No bogs,flat spots or anything like that,I like the carb.Real smooth,linear pull when I get on it!Good luck!
John

 

What Holley did you have such big problems with? Any in particular? When I did my swap from the q-jet a few months ago, I was seriously looking at the Speed Demon too. The $$$ for an electric choke and fuel inlet fittings along with the carb shyed me away from it.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

I had problems with all the holleys i have owned.From fuel leaks to just not being able to tune them,even having friends that have had holleys forever,still couldnt get them to run right.I then went to Edelbrock carbs,and would use them again anytime.I chose the Demon after talking to many guys running the Demons on Nitrous motors,as I was in the process of building a juice motor for my Z.Many have had good luck with holleys,i just wasnt one of them.This is just my personal experience,and yeah the Demons are expensive,but I was willing to pay it,in hopes of having a carb run right,and be able to tune it for my car.Sorry so long,Good luck!

John

 

How much is the fuel inlet system required for the Demon Carbs? It can't be too much, I'm not too worried about the electric choke.

 

The inlet kit is $80.00 for the good one and about $50.00 for the smaller size. Choke was about the same I think. This is for the speed demon. Road demon uses standard Holley inlets I think.

 

The inlet kit for the speed demon that i used was part #BGI-140020.It is 6 An and cost $45 thru Summit.Braided line with filtered inlets at the carb,real nice.I dont use a choke as I only drive my Z in summer so I cant help you out with a price there,sorry!Greearhr gave some prices though.Hope this helps you out,if not,give me a holler.

John

 

Yes... give or take a dollar.



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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

I used a demon once and let me tell you it kicks a** I lick my tpi better but, thats just what I like and if I went to carb that would be the one. Never ever use eldbrock unless you like to wast money.

 

So out of the box it will run good. What do I need to figure out what jets and rods I need for my particular setup. Does Demon have a table or something to figure it out? And I know this sounds dumb but how is the gas mileage (why get a demon if your worried about that right?). But seriously is it about 1mpg worse than Q-jet or what? Thanks

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305TBI FireBird, Holley Intake and TBI, Headers, Torquer Heads, Gears. Best E.T. 15.08 at 92.5, 0-60 6.45.(Before Heads)Summit cam purchased 204-214, to be installed "soon". And maybe a TPI swap,