Holley/Demon Carb stumble
What kind of manufacturing issues did you find? I really only played with one Demon carb and then that customer went to a flying toilet and alcohol.
The most common was the air bleed holes in the main body not being connected where the holes from the top are supposed meet the holes from the metering block side.
Also issues with the secondary linkage where you couldn’t get the rear blades to sit all the way closed.
(These were more of an issue with the Claw carbs).
On the RS models, which have replaceable boosters....... sometimes the counter bore for either the booster flange or retaining nut wasn’t deep enough and would allow the booster/nut to sit too proud of the gasket surface, which could keep the gasket from sitting flush against the body.
Creating a minor air leak which would erratically affect the tune.
Often behaving different each time to reinstalled the bowl/block.
I also ran into booster stake tubes folded over in King Demons(and BG reworked Holley 4500’s) along with some metering blocks that had been damaged during some machining operation...... and they had attempted to repair it with epoxy....... and the epoxy had run into the main well.
(That was on a brand new King Demon I bought).
That’s not even mentioning how screwed up a lot of the calibrations were.
Not that they didn’t match the specs in the catalog...... but how they were calibrated just sucked.
It wasn’t uncommon at all to mess with one for hours on the dyno, try all kinds of stuff to get it sorted out....... only to bolt on an equivalent ootb Holley....... and have the Holley not have any issues.
Early on there weren’t very many different models.
There wasn’t anything “affordable” that had adjustable air bleeds.
And the Speed Demons often were way way lean, and didn’t idle well with any kind of cam.
So, I got to where I’d install adjustable air bleeds in them and tweak the tune up before even bolting them on the motor.
I’d say the one area where BG/Demon really excelled......... was marketing.
Those big full page ads in the National Dragster and car magazines were pretty convincing.
The actual product however....... I found to be lacking more times than not.
The last Demon I was running on anything was an 850DP Mighty Demon I took in trade.
Apparently it had been being used on a 440 with no luck.
I don’t know how they arrived at the calibration they had in it(which made no sense at all), but I put some new gaskets in it, put what I felt was a more normal tune in it, and started using it on the dyno.
I got it dialed in with a little use, then it became a carb I used regularly as a dyno mule.
It worked well for me for a few years like that.
I was getting to where I was pretty “carburetor rich”, and figured that would be an easy one to get rid of ....... so I sold it.