What carburator do i need
 

I have a 3400 pound car i am building a 355 , 450hp motor , car has 456 gears with a 350 turbo, 3500 stahl, motor rpm will be about 6800 I was looking at the quick fuel 750 carb the q series, but i see there is a down tube and a annular what is better for me will be running it mostly at the track thx to all

The annular booster is more of a drag only set up, so it would suit your needs better than the convetional booster.
The 750 dp quickfuel would give excellent throttle response and is a nice picese for the price, it has a billet base plate and metering blocks it would work well on your set up.
I'd double check the primary accl pump cam though I've seen 2 come straight out the box that were installed backwards which made for a horrible off idle stumble. Goodluck, Charles