BBK Performance 3501 Twin 56mm Throttle Body - High Flow Power Plus Series For Ford F Series Truck And SUV 302, 351 BBK is your Number One Aftermarket Performance Brand in the USA - American Designed and Built High Flow Power Plus Series Twin 56mm Throttle Body Increases Airflow to Improve Horsepower, Torque and Throttle Response Over Stock Recommended For Vehicles Where Modifications Have Been Made or are Planned Especially Cold Air Intakes and Exhaust All New CNC Machined Casting Assembled with Components that Exceed OEM Standards, They Will Offer Years of Trouble Free Performance Simple Direct Bolt on Replacement for Factory Unit with Simple Hand Tools in Less Than Half an Hour