GM TBI There is a color coding on the top of the injector, in the center of where the electrical connector goes, that does wear off, but is the flow rate code? Grn/Wht 305 CID eng about 40 #/hr Org/Blk 350 PU about 55 #/hr Yel/Brn 350 Cop Car about 65 #/hr Blu/Blk Late BBC PU about 80 #/hr EarlyBBC PU about 90 #/hr Purple?? Ken Murillo fisystems at aol.com