I'm attempting to build a transistor ham band receiver as described in a 1959 article from QST. As you might expect, finding all the vintage components has been quite a challenge, but I have managed to find most after a couple years of searching and collecting. The one part I can't find is the Collins F455A-3 mechanical filter, which has a 3 kHz bandwidth. The ones I am able to find mostly have wider bandwidths and are crazy expensive on eBay. I was wondering if I can use a readily available (and cheap) ceramic filter in its place, such as the Kyocera KBF-455P-6AS. It is the same frequency and similar bandwidth. Would it be a drop in substitute or would the circuit require extensive modification? The filter would go in between the second and third IF stage.