So you mean a 68 Fury 440 (non-wagon) would have the big one this car has, or this unsilenced one I circled in red?
The yellow says both 383 and 440 in P and D carlines would be snorkeled. I know Nick's info isn't 100% complete and correct, but it's one of the best compilations I've ever seen.
I'm not trying to say you are wrong, maybe it's just because that big unsilenced one looks so wrong on a C-body.
If it is correct, I wonder if it is taller than the A-body version, ala 67 B vs C dual snorkel.
Nick's Garage - Air Cleaner Identification
A Plymouth Fury factory 440 "L" code 375 HP engine car (non-wagon) would have the small diameter unsilenced air cleaner except for early production cars. Don't know what year California started their noise level crap but if in '68, California cars would have gotten the dual snorkel pie tin air cleaner. Chrysler & Dodge C Body cars did not use the unsilenced air cleaners. Fury wagons with a "K" code 350 HP 440 as well as Dodge & Chrysler C Body cars and C Body cars with the 325 HP 383 engines used the non pie tin dual snorkel air cleaner and "L" code 375 HP Dodge and Chrysler C Bodies used the pie tin style air cleaner in 1968. I know that some police cars were special ordered with the dual snorkel air cleaner and suspect many 440 Fury owners complained about the noisy unsilenced air cleaners and likely had them swapped out.
I am going by memory. When I converted my yellow '68 Sport Fury from a 318 car to a stock appearing 440 (really a 520") I researched this issue using a '68 Chrysler Parts Book.