SpeedFactory B-series upper fill necks are designed to be used with custom radiator setups (such as the SpeedFactory tuck radiator). These are made with high quality billet aluminum machined flange and filler neck. This changes the high point of the cooling system for easy fill of the radiator.

These are offered for B16 and B18C-GSR head applications with optional stock 32mm neck or -16AN fitting.

Radiator Cap sold separately.