Help buying a used carburetor (WIW and what to look for)

I'm pretty new to tinkering with engines and especially carburetors, but I am mechanically inclined and educated. Here's the situation:

I want a new carb for my stock 440; the old Carter (I think) just isn't cutting it
After reading on FBBO and elsewhere, it sounds like 750 CFM is the size I want.
Car is a 68 Charger
Engine is supposedly out of a 67 Imperial and is stock
I was thinking about spending $300-$500 brand new on Summit but found the following carb for sale nearish to me:

Demon 750 with vacuum secondary


The guy says "No need for rebuild,no leaks,bolt on and go". Told me over the phone that it hasn't given him any problems (of course), that he's upgrading to an e85 850 CFM. He couldn't tell me a model number; said he didn't know and couldn't find one. I think it is either a 750 "speed demon" or "road demon".. can't really tell which.

I know basics like to look for stripped threads and broken/bent/warped pieces... but that's about it. What do you guys think? What's it worth? What should I look for? What should I ask?

Thanks for any help/advice. :hello2:

www.demoncarbs.com, hi verdelaw, I have two demons and they work great. website should tell you what you need to know.

Looks like a clean carb. If it came off a running engine recently should be good to go as he said. And if the price is no more than 50% of new then not a bad deal at all. 750 vac secondary is a good choice for a 440.

Well I'm thinking that it's a scam of some sort now.

I had called and texted him and he seemed fine, but then he wanted to meet at some truck stop early in the morning... then when I started asking about where the choke plate was and about what looked to be a missing screw or two all the sudden he tells me that he doesn't have it any more and he went to look for it on the shelf and his wife had sold it to someone without telling him. Seems a little strange. Plus his ad had been up for nearly a month.. and is still up.

http://stlouis.craigslist.org/pts/4980093769.html

My wife wouldn't know what a carburetor looks like, much less be able to sell one. But hey, maybe it's true.

Ad is deleted now.

You can get a rebuilt / reman 750 edelbrock from Jegs for $269.00 with free shipping.

I have a holley 750 vacuum secondary with feed line and pressure gauge I would let go for a reasonable price.

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It's nicer than the one above.