You saw what mine measured. It's a factory 340 car. I don't know what the difference is between the two. Are you measuring just the opening for the radiator? I've been looking through all the sources for a factory 26 inch radiator support in an A body. I'm not having much luck at finding any information. I measured my friends 318 Duster, and another friends 340 Duster and asked another friend of mine to measure his 71 340 Demon and all measurements were 22 inches. Maybe you or someone else on here can find out why there are discrepancies. Would a factory A/C car have a bigger radiator support and 26 inch radiator? Maybe I can find the answer with some digging.