You can get the full part # for 9C675 from this page: Documentation/Fuel Systems/Air Cleaners/
Air Cleaner Tube #'s. With that you may be able to find NOS parts.
However, the check valve in the vacuum line on the snorkel hasn't been listed on the site. So, I've added a new page: Documentation/Fuel Systems/Air Cleaners/
Air Cleaner Check Valves. Please check it out to see if it works for you.
Gary, AKA "Gary fellow":
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Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI