Quick – close your eyes, and picture a carburetor. Odds are that your mental image was of a Holley [1] 4150-style carburetor, and for good reason. They’ve been mixing fuel and air for pretty much as long as we’ve been racing cars, and Holley’s carbs are the yardstick against which all the other competition is measured.
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Main Body Features:
- Integrated Idle Bypass Valve eliminates the need for holes in the throttle plate
- Air bleeds moved outward for smoother airflow transition
- Contoured hex head squirter screws
Fuel Bowl Features:
- 20% more capacity compared to traditional V-bowl
- Built in drain plug
- Internal baffling to reduce sloshing
- Fuel shelf below needle and seat for more consistent metering
Metering Block Features:
- Billet aluminum construction for better gasket sealing
- Excess material removed for increased fuel capacity
- Power valve channel restrictors machined lower for improved fuel delivery
Of course, being synonymous with carburetors doesn’t mean that Holley has decided the race is won, and they can simply coast. The opposite is true – they’re working harder than ever to perfect their carburetors, and those efforts are obvious in the new Ultra HP line. Available in 600, 650, 750, 850, and True 950 CFM sizes, they’re packed with features born from years of experience, both in-house and from the thousands upon thousands of racers who rely on their carburetors.
Highlights include:
- Aluminum construction – 4.5 pounds lighter than previous zinc carburetors
- 6061T6 billet aluminum metering blocks and base plates
- All new fuel bowl design
- Updated main body design
- Elongated dual-pattern mounting holes on baseplate for use with 4150 or Dominator style intake manifolds
- Dedicated race-only throttle lever with unnecessary attachment points and tangs removed
- Knurled hand-adjustable primary and secondary curb idle screws
- Choice of 1:1 or progressive secondary throttle actuation
On top of the long list of mechanical upgrades, Holley is also introducing a new Hard Core Gray finish available on main bodies and fuel bowls (with black billet metering blocks and baseplates.) This hard coat anodizing is a first, and it actually penetrates the aluminum for superior corrosion protection. Also available are shiny aluminum bodies and bowls with a choice of black or red billet baseplates and metering blocks.
[4]The Hard Core Gray anodized finish is also available on many other Holley carburetors like this Ultra Dominator.