BBK 1534 Twin 52mm Throttle Body - High Flow Power Plus Series for GM 305/350 TPI BBK is your Number One Aftermarket Performance Brand in the USA - American Designed and Built High Flow Power Plus Series Twin 52mm Throttle Body Increases Airflow to Improve Horsepower and Throttle Response Over Stock Recommended For Stock Applications Where Few Modifications are Made or Planned All New CNC Machined Casting Assembled with Components that Exceed OEM Standards, They Will Offer Years of Trouble Free Performance Bolt on 8-12 HP Fits all 305 350 TPI GM Applications, Camaro, Firebird, Corvette