[lluciano77]

Are they good carbs for street use on a high compression 404 SBC?

How is the bottom end?

Has anyone been able to retrofit a choke on one of these carbs?

How about the 750 CFM annular model?

[mstngjoe]

The 0-9381?

In addition to no choke, no vac ports for dist advance or pcv. May not be an issue for you though.

The annular booster carb should have a good bottom end. That particular style booster responds better to a weaker signal compared to a down leg. But it's a bit more restrictive in the higher rpms.

More race than street I would think.

If you're looking for a good street carb, you might consider the 3310. It's a vac secondary 750 and has a choke.

[lluciano77]

Yes, I was refering to the 0-9381.

I am using a 730 CFM Holley. It is a #4609. It has bell shaped truck boosters in the front and downlegs in the rear. It works great, but I want to see how my car will respond to more CFMs.

All of the Holley DPs 750 CFMs and above have downleg boosters. The downlegs flow well, but they sacrice a ton of bottom end metering. That is why I am looking at the annular boosters. They will still flow and meter well.

I am also going to try a 4778 with the smaller bell shaped boosters. They are not as big as the ones on my 4609, but they would serve the same purpose.

What I am trying to accomplish is to have a carb that will flow what I need it to up top, but also meter well at lower RPMs. I have a really broad torque curve, with higher than normal hp and torque figures for a street driven vehicle. The idle is very smooth, and my vacuum is high (22" out of gear and 15" in gear).