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Discussion Starter #1
I'm looking at a trade, the other guy has what he says is a Demon 750 carb. I know nothing about them. He says there is no model number, that the early ones didn't have model numbers. Here's some pics. Is it a 750 and what is it worth? Does this old style use Holley jets and what not?
 

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I've never seen a Demon like that. Looks kind of like a Holley 4160. it's clearly a vacuum secondary carb.

Might ask for measurements on the diameter of the primary bores. All of the Demon 750's I've seen have a primary bore diameter of 1.688" (or not quite 1 3/4"). The catch is that the 650cfm models also had the same primary bore. The 850 cfm Demons are dead on at 1.75" primary bores.

See here: https://www.holley.com/products/fuel_systems/carburetors/factory_refurbished_carburetors/parts/FRSDA-750-MS

If it's smaller it's not likely a 750 cfm model.

I'm honestly not sure if any of this applies to that carb. It looks like a pretty old model. before you buy it I'd make sure you can get parts for it...it likely needs a rebuild.

Edit: That's a Road Demon Jr carb. Not available in 750cfm (only up to 725cfm). See here: http://www.wpsracing.com/derodejrca.html

I'd probably pass on that if I were you.
 

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Discussion Starter #3
Thanks. I didn't even notice at first but I looked to see if it was a double pumper and it looks like the secondary squirter is missing.

Demons that look like it on Ebay and have no model number mostly say 650 and they are in the $75 to 150 range. They must not be very good.
 

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I think the typical 750 Holley carb or clone (which the Demon is) has the 1-11//16" throttle bores that hutchenc mentioned.

Demons use the same jets as Holley, but not all other parts are interchangeable.

Holley owns the old Barry Grant carb line now, which the Demon is part of - but I have no clue if they fully support it.
 

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Thanks guys, I'll pass on it. Even though all I'm trading is a BBC Edelbrock performer intake spread/square bore. (Not the RPM model.) I think I can do better.
 

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I've been running a 650 Vac secondary "Speed Demon" for years.
It's a good carburetor (but... it's still not FI !!).

I think if I were to buy a new carburetor I'd look very hard at the "Street Demon".. with it's smaller primaries and big secondaries. It's pretty much a refined Quadrajet.

As for this carburetor, I'd pass...
 
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