No, to have something to bump it above the CPUs supported multipliers would require the interposer to have a separate bus that would run higher than the motherboard's bus and then somehow translate that to the socket on the motherboard.
I also have a dual Socket 7 motherboard and I do have a couple of those interposers that came with AMD K6-2 CPUs.
A K6-2 will not even post on that board.. at least not without an interposer. I tried quite a few different models. I haven't actually tried it with an interposer though. If it does work, then it is highly unlikely that it would work with 2 of them.
One other option would maybe be to get a couple of the 266Mhz Pentium MMX CPUs. The Tillamook Socket 7 version is more common but apparently some laptops used a mobile Pentium MMX 266 that was soldered onto a Socket 7 interposer.
https://www.cpu-world.com/CPUs/Pentium/TYPE-M … tium%20MMX.html
I'm not sure how the 4x multiplier would work on your current board or if it would even post or work properly without a modified BIOS.
If you wanted to try to run your board at 75Mhz, it would require you to swap out the clockgen with a pin compatible one that supports higher bus speeds.
Or you could even compare datasheets and wire a different one up even if it wasn't pin compatible.