Im in need of a race carb and I found a 750 speed demon for sale kinda close to my area but wanted to make sure these were even a reasonable option? My motor is an old school 383 with TRW pistons, I think the cam is a 520 something lift Lunati and stock 906s in an A body with 5.13 gears.

With all the bad reputation stories about Demon carbs I would stay away unless it's a deal you can't refuse
Holley 750 DP carbs are pretty easy to find used
Gus

I have one, I had to replace the main body because the metal is so soft where the squirters go in. other than that it ran fine. I would stick with a holley though

ran my 850 pretty much out of the box for 5 years,last year i put a wide band o2 sensor on before i switched to e-85 and its ritght on.foot brake car in the low 11's.i'm going to use it on my street beater.

There is a reason he is selling it.... most of the
times it was because BG stuff was bad... usually a
quality control issue... I dont buy BG stuff due to that

i have a mighty demon on mine. it's a good carb, once you work out the kinks (it only took a few years). my pump squirter holes stripped out, and i found a supplier in florida who had the appropriate inserts (the only supplier in the country, far as i know). like all bg carbs, it was FULL of metal. i've seen some with cross threaded jets, throttle blades installed upside down, it seems their problems are usually assembly related. i've done a bunch of them, from speed demons, all the way up to race demon rs. they always have metal in them, and some kind of assembly error.

Sounds like I'll be passing on that one. Thanks guys.

I have a 750 3310 vacuum secondary holley that they sell a conversion kit for at speedway for like 130 is this a reasonable option? I'm just a broke college student or I would just go by a new carb...

I have heard all of the horror stories also about BG. I have a 1090 & a 1290 King Demons & have never had any problems with either one. Now that Holley owns BG most everything is available for them again.

The R-3310 750 Holley will work just fine for you. It should be a dual inlet carb, so you might have to change your fuel line on the inlet side when you add a secondary metering block. The kit shouldn't cost more than $50.00 and it allows you to change jets on the secondaries. That's all it does.
There is also an aftermarket metering plate that uses regular Holley jets, doing the same thing maybe for less.
You don't need to change float bowls for either choice.
If you're REALLY bucks-down you could drill and tap holes into the metering plate and use Holley jets.
1/4-32 is the thread size.
Spend money on springs for the vacuum secondaries, too, for tuning.
R.