[DeTomaso] Demon Carb Feedback Wanted

[Daniel C Jones]

> Any users of this thing out there?

Demon carbs seem to suffer from quality control problems.  Lots of
stories of people unable to get new Demon carbs to behave.  When they
disassemble them, the float bowls have shop grit in them.  That said,
I've driven Demon equipped engines similar to yours that ran great.

>From the photo I don't see an electric choke, so how's that work?

The idle circuit and accelerator pump are sufficiently rich that you can
usually get it to fire without a choke, at least in moderate weather.
You'll have to pedal the carb to keep it running, though.  If you go with
a carb without a choke, make sure you get a multi-strike capacitive discharge
ignition (MSD-6AL, Mallory Hyfire, etc.).  With your engine, you should
have one of those anyway.

> the electric choke seems to work up to the point of "make me feather the
> throttle until I hate it" until the car warms up.

Demon makes carbs without choke horn, with choke horns but without choke
plates and with choke horns and choke plates.  Sounds like you want one
with a choke horn and the optional choke plate.  Be aware Demon carbs flow
more than their CFM rating (i.e., a 750 Race Demon would flow more than a
traditional 4150/4160 750 Holley).  Holley HP series carbs also flow more
than their ratings.

> My car had an Edelbrock carb when I bought it.  I think it was the 650cfm
> model.  I didn't check.  It ran okay, but when I changed the heads and cam,
> it ran like crap.  I didn't want to learn a new carburetor, so I switched
> to a Holley 650dp.

This is pretty typical when asking for carb user experience.  Most don't
take the time to fine tune them for their application.  One will get lucky
and have it be close enough for his application and will praise the carb.
Another will have it run lousy and will knock the same carb when a few days
of tuning with a wide band O2 sensor would have had the carb running great.

> I considered Demon, and while they're probably built better than Holleys
> they don't share that many parts - so if you need jets, power valves, etc.,
> you have to order them - probably not a big deal.

This is not true.  Jets, power valves, squirters etc. are all interchangeable
with Holley.

> OK, Any feedback on Edelbrock 800 series?

It's just a larger CFM version of the 750 CFM AFB.  AFB's are very reliable
carbs and are easier to tune than Holleys but generally make less power
for the same CFM rating.  They are also less adaptable to large cam overlap.
Another carb worth looking into is the Quick Fuel Technology Holley clone.
QFT carbs are made of aluminum (lighter), accept the usual Holley tuning
parts and have provisions that allow you to change the power valve channel
restrictions and idle and high-speed air bleeds for fine tuning.

Dan Jones