My 75 C10 SWB MIGHT have originally had a cat...I dunno now though...if you guys say that it will say "CATALYST" on the radiator core support Emissions sticker..then I DIDN'T originally have a cat, cuz my Emissions sticker only says EGR, EFE, and OC Exhaust". But I figured OC Exhaust meant a cat, but maybe it doesn't...
