Generic 4150 Carburetor 650 CFM 4‑Barrel – 1-11/16" Square Bore, Mechanical Secondary & Electric Choke

Generic BR-67255 is a 4150-pattern, 650 CFM four-barrel carburetor with a mechanical secondary and electric choke made to replace Holley/Quickfuel Brawler-style units.

This high-flow carburetor is built for street and strip engines that require a 1-11/16" square-bore flange, reliable cold starts, and predictable throttle response. It combines a split dual-inlet bowl design with sight-glass windows so you can set float levels without removing the bowls. Finished in lightweight die-cast aluminum, the unit balances low weight with heat resistance and corrosion resistance for long service life.

What engines and intake manifolds will this carburetor fit?

This BR-67255 follows the 4150 square-bore flange standard and is intended for engines that need a 650 CFM carburetor with a 1-11/16" throttle bore. It replaces similar Holley/Quickfuel Brawler double-pumper and other aftermarket 4-barrel carbs that use the same bolt pattern and spacing. Always verify flange bolt locations and throttle/accelerator linkage before installation.

• 4150 square-bore flange pattern (standard bolt spacing)
• 1-11/16" (0.0625" per step) throttle bore size for 650 CFM flow
• Designed for performance street/strip V8s and crate engines
• Mechanical secondary throttle for consistent high-load response

How does the electric choke and mechanical secondary affect drivability?

The electric choke improves cold starting and idle stability by adjusting the choke plate electrically until the engine warms. The mechanical secondary uses a direct linkage so the secondaries open progressively with throttle input, giving more predictable power delivery than vacuum-secondaries on hard-throttle events. Together they help produce consistent starts and linear acceleration when tuned properly.

• Electric choke simplifies cold-weather starting and idle tuning
• Mechanical secondary delivers immediate throttle response under load
• Dual inlet bowls reduce fuel starvation during hard acceleration
• Sight-glass float windows let you confirm fuel level quickly

What are the key specifications and tuning points I should know?

The factory setup uses primary main jet #70 and secondary main jet #74, a typical baseline for many 650 CFM applications; final jetting will depend on engine displacement, cam profile, and intake design. Float level, idle mixture, and accelerator pump tuning are the primary adjustments to dial in drivability. Use the sight-glass windows to set float height, and follow standard jetting steps if you change elevation or fuel composition.

• Rated 650 CFM with 4-barrel, 1-11/16" bore configuration
• Primary main jet: #70; Secondary main jet: #74 (baseline values)
• Dual inlet fuel bowls with sight-glass for float adjustment
• Die-cast aluminum construction for reduced weight and heat resistance

Who this carburetor is for: Builders and tuners who need a drop-in replacement for Holley/Quickfuel-style 4150 square-bore 650 CFM carburetors, especially on performance V8s used in street, strip, or restoration projects. It suits engine builders who want an electric choke for easier cold starts, a mechanical secondary for aggressive throttle response, and visible float sight-glasses for quicker setups. If you plan to modify jetting or run different fuels, this carb provides a familiar platform with accessible tuning points and aftermarket support. If you are unsure about fitment, double-check your intake flange pattern, throttle bore measurements, and linkage geometry before purchase.