I used a Demon on a car I just built for a friend. It's just a street driven 350, I used a 750 DP Demon.

I found it to be a very attractive and well made piece. Good quality. Not really any standout flaws. Contours and throttle action are smooth

It had some cool features, but the only one that seemed valuable to me was the 4 corner idle, as opposed to the 2 corner of a comperable Holley. The rest are either found in competetors as well, or are pretty much sounds good-does nothing features. But, the 4 corner idle is very nice to have.

It did bolt up and run quite well out of the box. Not perfect, but good. Every circuit is still needed some tuning. I've always said there is no such thing as an "out of the box" induction period, so that doesn't bother me. Advantage: Draw. They can't make one carb to fit every motor untouched, and demons are no different.

I'd have to give power potential a draw with Holleys. They use basically the exact same design. Most dyno tests put the Demon a few (2-5) ponies better, but I don't really buy it. I say the only difference is that Demon cheats when rating thier carbs, using wet flow instead of dry like anyone else. All it means is that thier "750" carbs are a little bigger than a 750 of anything else, not that they actually function ANY better.

Price was no contest. The Demon was a full $100 more than a Holley double pumper. It should be noted however that Demon charges the same for different cfm of the same carb, Holley doesn't. If I had used a 650cfm, the difference would have been ~$150. I also found out that Demons use a different inlet fitting than anything else, one you can't get cheaply. The fuel line I used cost $100. The one for my Holley was $10. You kinda have to count that in the cost difference. That puts the cost up near what Holley charges for a 4150HP.

Is the Demon a good carb? Yes, it is. Outstanding quality. Is it worth it? would I buy one again? I'd have to say definatly not to both, altho I'm sure others would disagree. The pluses it has over a Holley are not nearly worth the cost difference. If you have some need for cool features, and don't mind spending the extra cash, then spend a little more and get a 4150HP, you get more for it.

 

Isn't Holley doing wet testing also? Thought I read somewhere that they were now.

 

Holley released the Street Avenger series to try to compete with Demons niche directly a bit. Looks prettier, has a few more features, costs alot more. I have about the same opinion of the SA as I do about Demons too.

SA's are wet tested. thats why they're called a 670 instead of 650, 770 instead of 750, etc. Normal holleys are still dry.

 

I thought that the Street Avenger line is being produced to compete with Edelbrock because Holley thinks everyone who buys Edelbrock wants an easy, reliable, street friendly carb; and that's what they are trying to achieve with the SA's.

 

Some competition... the Holley SA are at least 100 bucks more, but still worth it. Just get a VS Holley. They're all over the place and easily compete with the edelbrock carbs.

 

Good info. Good review. I knew there was a reason I still run carbs I buy out of a junkyard or swap meet. This is it. New is a lot more expensive than old and mixing air with fuel really hasn't changed much in decades. The only PITA thing about old carbs is replacing worn out throttle shaft bushings. Not a do-it-at-home kinda job.

I like the look of these "tuner" carbs and would love to have on if I was going for 'pretty' as well as 'fast.' But if I have to choose between 'pretty' and 'fast', well, let's just say that 'fast' wins hands-down.

 

Wouldn't wet-flowing the carbs REDUCE the CFM?
Wouldn't a 650 return like 630 CFM when wet-flowed? Et cetera.

 

Probably would have been better to say "770 instead of 790, 670 instead of 690", etc. But, they don't market 790's or 690's, so...

"Review" is probably the right choice of words. A "comparison" would have bolted a Holley 750 DP on the same engine, tuned it, and compared the performance of the two.