The Street HP uses the best features from Holley's race Bred 4150 HP carburetors, but tamed for street and light competition use. The contoured main body from the 4150 HP has a tumble polished shiny finish. The metering system includes a timed spark port for a vacuum advance distributor and is calibrated for a hot street and strip engine setup for outstanding throttle response and drivability. A street HP base plate is used so there are plenty of vacuum ports for power brakes, PCV, etc.