Not necessarily a pure drag race question, but Im getting closer to dropping in another engine into my maverick and I've acquired a demon carb to use on it. Pros and cons on demons? It'll see more street use than actual track- that being said, I've swapped to a 5 speed and I'll be flogging it regularly. It's a fun car and that's what it'll be treated as. Just wondering who's using them and what y'all think of them. Thanks!
Demon is out of business (Barry Grant). To my knowledge, Holley has taken over. That said, I've never seen a Demon that impressed me, unless it was re-worked. They all ran and drove but every one of them was "off" in one way or another until a tuner that knew what he or she was doing lined it out.
I've had two Speed Demons, one a 650 and my current 750 on my 302. In my opinion they are both bad ass carburetors performance wise. My 650 which I purchased from Craig's List is an old stock unit from when Barry Grant owned the Company and they were having quality issues. The first owner had the 650 on his 350 chevy and claimed it was too big and never ran right. The carburetor had several issues externally and internally due to the tampering of the previous owners carb "expert." The choke system on the Demons are not the best and most times requires modification of your air cleaner to prevent linkage bind. It still gets the job done though but not as precisely as other brands. In my thinking, most of the quality issues were brought on by new owners of the product not knowing how to dial in a carburetor that was different than their old 600 two idle screw Holley.
I`ve worked with 3 of them the last couple of yrs,I think they are good carbs,just don`t over tighten the fittings going into the bowls.One of em,an 850,was on a 454 in a nice little chevy drag truck,full tubs,13w 31t slicks,9in. 4.56 gear & a trans brake glide & a cage.Truck went 7.2 in the 1/8 with no tuning & a sorry marine cam that fell on its face at 5500,worn out slicks.If the owner would have listened to my friend &I,let us put in a lunati bracket master cam,with tuning & new slicks I have no doubt that combo could have turned low 6 or high 5s in the 1\8th.You can lead a horse to water but it does not always drink,guy got disgusted & sold the truck.I`m not a chevy guy,but this was a nice truck that with a little work could have been a bracket killer with some one that could drive it,only 2300ibs with that big blk(nasty).
Ive had a 750 Speed demon on the 393 in the cobra... worked excellent and I have a 750 Mighty demon on the Mav... works good.
I like demons too. Just like a Holley.. really nice flowing low resistance carbs if you grind mill off the choke tower. Always liked the smoother exterior design.
The good..... Demons always appear to work good out of the box..... They have excellent throttle response..... The bad..... They are not great performance wise the way they come..... There calibration is always way rich, but it's not as simple as jet adjustments..... They really need a complete recal, I always end up changing high speed and idle air bleeds along with idle feed restrictors and jets..... I have had one that needed a emulsion circuit adjustment too..... Who ever does this really needs to know what they are doing..... I am basing this on at least 3 sets of test passes at the track with 3 different cars, all using an out of the box Demon against an out of the box Holley the same size..... And we are talking about 2 to 3 tenths difference in ET in the 1/8 mile, more in the quarter.....