ORIGINAL: Adil Nasim
Depending on how small the size difference, your problem is actually easier to fix, Just cut some slots in the intake, slide the fan in, spot glue some FG cloth on top of the slits / cuts and let dry. All Done

Now, if you tell me that your inlet is only 3", you DO have a problem

Adil
It's actually 5" even. Whish I ahd a Dynamax laying around. That extra 1/8" on the Ramtec makes it a real pain in the ***** to
install.