Here is the carb that I run on my Autocross\Hillclimb car. It's got a few unique features that you may find interesting.

This started out as a Holley 3310-1 780cfm VS. Originally started out with Quick change Primary and Secondary Fuel bowls, Quick change Vac Diaphram pot, vent whistles and the normal shooter\cam mods.

Now the 3310-1\2\3 series is known as a lazy carb. Originally designed for 396 Big Blocks and has a rich transition curve.

One of the first mods I did was to install Annular boosters in the Primary side. This really perked up the throttle response ( due to better booster sigmnal ) and I was able to reduce the Primary jetting two sizes. I left the " Dogleg " boosters in the seconadry side for two reasons.

1) By the time the secondaries open, airflow rate is fairly high. Gains from adding Annular Boosters would be minimal.

2) Most important. Annular boosters would disturb the airflow arounfd the pitot tube that draws from the secondary side. Holley went through a lot of engineering in the design of their VS carbs. I'm not about to second guess them.


The biggest change was adding a " Weber Power Plate " conversion to the Primary side. These were made in the 1980's by the famous Weber Carb company in Italy. This replaces the rather simple Holley metering blocks with all Weber components.

Idle jets, Emulsion Tubes, Main jets and Air Bleeds are all easily replaced. It takes us about thirty seconds to do a jet change..... and you can do it with the engine running!!! Fuel curve is far superior to the regular Holley 4150 series. The Weber Conversion changes a 4150 series from a two circuit carb to three circuit carb just like the Dominator series. With a 4150\4160 series the idle circuit is shared with the Transition circuit. You have an entirely separate Transition circuit with the Weber.

Change in the throttle response was incredible. Most people who have driven my car expect to find FI under the hood, the throttle response is that good. Fuel milage took an increase as well.