I just wondered if any one has used a Demon Carb on their 350. I Think that the changes that I have made to my engine have made it impossible for my Q-jet to keep up in its current state of build. I would have to send my carb to some one to modify and I don't think that I want to spend any more money on a carb that has been out of production for more than a decade now. If you have used a Demon Carb on your 350 what type did you use? A Race Demon, Speed Demon? Does your carb have vacume secondaries or mechanical double pumper? Let me know soon, as I will probably be ordering one this afternoon. Also let me know if you have any gripes about it.
Absolutly no gripes on the demon carb...here is what you need for your application: If you have an auto trans go with the vacuume secondaries speed demon. Mechanical secondaries are for manual trans cars. Race deomons are only used on racing applicatins and are not set up for street use. I currently have a 750 Speed Demon on my 350 LT1 425 HP small block chevy (sorry about the chevy), I've used Edelbrock carbs (around turns they bog down) and I have used Holleys (constantly tuning forever). The Demon I SWEAR by, its the best carb for the money and the BEST one I have ever used. Oh BTW I do have an 850 Rochester Q-Jet on my Buick 350 and I swear by a CORRECTLY rebuilt Q-jet. Q-jets are great because once there set, its set for life...also they have small primaries (great on fuel economy) but dump the secondaries and your gone. I'm didnt go with the Q-jet on my Chevy motor because its got too much power for the small primaries of the Q-jet. Believe me I tried 600, and 650's on that motor and it drank the bowls dry at idle, thats why I stepped up to a 750. Hope this helps you out with your decision :TU: Larry
Thanks for the response Larry I don't know what the set up on your buick 350 is but I'm running 10.1 to 1 compression and a decent cam. The problem I'm running into is getting the Q-Jet to not run lean on the different circuts. No matter How I recurv the timing I get pinging one place or another. I think the fuel curve is just wrong. Does your Chevy 350 have a vacume sec. carb on it? Thanks again for your response.
I have a vacuume secondaries on it...runs absolutly perfect. What it is that if the trans is under stress, the secondarys on the vacuume setup will sence it and then open slowly based on the demand. It more of a fluid transition and the car performs MUCH smother with the power band of the motor. The manual secondaries are for manual trans because you always have to down shift and have the controlls at the stick to up shift and down shif the car + reving a bit to bring up the RPM's to down shift. If your having problem with a lean condition as you rev up, sounds like you have small secondary jets...in order to corret this try contacting a performance shop that KNOWS how to fix it...I stress the KNOWS part because lots of people can tune Holley and Ededbrocks, but Q-jets are a different story. I have a Q-jet on my Buick 350 now and I'm really content on the performance, no bog, no lean condition, no problems what so ever. I even race the car with the Q-jet and its smooth as glass. I had it bilt at a small garage around where I live...the guy has been doing Q-jets for over 40 years, so he really knows his stuff. All I had to tell him was the combo on the motor and trans and gears, and he set it up correctly. I did't have to touch a thing when I bolted it on the car...ran #1 from the start. Hope this helps you out a bit..Im sure somone here can tell you where you can get your Q-jet rebuilt correctly, you will be much happier :TU: Oh BTW my buick 350 is 10.25:1 compression...complete rebuit with TRW high perf stuff, 30 over, decked, new crank, and just about everthing else :laugh: I paid 2,500 to make it great for the street, but hold its own at the track. And I cant forget the trick 850 CFM Rochester on it (its a rare find to have one). Oh 1 more thing, it only cost me $100 bucks to get my retuned and rebuilt, so the Q-jet is cheaper in the long run, as opposed to 450 it cost me for the Demon. Larry
