[Collins] AM Mech Filter for 75A-3, or LC net?

[Guy Olinger, K2AV]

Looking for an AM mechanical filter for my 75A-3. It is being used
with a Johnson Ranger & Courier, CW and AM. Not using it for SSB at
all. At some point I will get something S-line for Collins SSB.

The 75A-3/Ranger is a match for the first Ham rig I ever saw as an 11
year-old.

I got to operate it on ten meter phone with my school friend's dad, W8
something, standing behind me. Had to move shortly after followed by
three years of desperate family circumstances, but was hooked forever,
and had a novice license at 14 due to the friendly ham shack of K4PNF
(a real stand-alone shack with nuthin but radio in it).

The 75A-3 currently has a F455B-08 and a F455B-3. The -08 is fine for
CW. But the -3 is pretty narrow for AM, though just fine for SSB.

Looking for a F455B-6 or a F455B-8 (think I have seen those mentioned)
for outright purchase or to trade for the -3. I can only use two
filters, as you know.

Any corrections or tips about this appreciated.

I realize some folks have used an LC filter in place of a mechanical
filter for this, but I have no information on that, or on the relative
merits.

73, Guy.