Introducing the most powerful and versatile racing air cleaner bases for Holley 4150 4 barrel applications! You can bolt-on double digit power gains!!! Precision Booster Signal and entry profile Increases torque and provides crisp throttle response, improved pull out of corners and additional straightaway speed.

9 rear wheel horsepower gain on a 604 Crate!!!

16 engine horsepower gain on a Dirt Modified!!!

Months of design evaluation and flow bench testing, followed by extensive dyno and track tests (now over 400 independent pulls!) conducted by the most respected names in race engine and carburetor assembly, have resulted in the best flowing, highest power producing air cleaner bases for Holley 4 barrel race applications. Every application from Stock Cars to unlimited Late Models and Big Block Modifieds have achieved significant gains in power and response/driveability.

R2C engineers developed each precision base shape to augment the venturi profile of the popular 4150 series Holley carburetor, resulting in dramatically smoother entry profiles and reduced restriction and a much stronger and consistent venturi/booster signal, allowing precision racing carburetors to perform at optimum levels and engines to produce increased power and torque. When used in conjuction with R2C Late Model/Modified air filter configurations, nothing comes close to the performance advantage R2C CFD 4150 4 barrel bases offer racers in applications from Stock cars to the highest horsepower open engines.