Bad idea.
The '040 uses a 32-bit data bus and the PowerPC 601 uses a 64-bit data bus. Usually the PPC upgrade cards had a large amount of cache (1MB or so) to offset the slow Quadra RAM. Taking that into consideration, the whole purpose of the PDS adapter for 6100 was to make the DOS card work. That's it. The signals that the PPC upgrade card would use to "take over" operations for a '040 probably aren't implemented at all.
Even if you were somehow able to get this to work:
1. There would probably be performance and reliability problems because of the shuffle of your RAM from 64-bits to 32-bits to 64-bits.
2. The power load from both the adapter and the upgrade card with a full CPU and cache may be more than the circuitry was designed to handle. (You may damage your logic board.)
3. It's unlikely the the adapter board runs at full PPC speed, but if it did then it would either make your upgrade card work at a faster-than-spec speed or cause weird timing problems.
4. G3 upgrades (even new in box) are cheap and readily available for this Mac. They would be several times faster and more stable than this arrangement could ever possibly be.
In short, there is no upside to even trying this.
The '040 uses a 32-bit data bus and the PowerPC 601 uses a 64-bit data bus. Usually the PPC upgrade cards had a large amount of cache (1MB or so) to offset the slow Quadra RAM. Taking that into consideration, the whole purpose of the PDS adapter for 6100 was to make the DOS card work. That's it. The signals that the PPC upgrade card would use to "take over" operations for a '040 probably aren't implemented at all.
Even if you were somehow able to get this to work:
1. There would probably be performance and reliability problems because of the shuffle of your RAM from 64-bits to 32-bits to 64-bits.
2. The power load from both the adapter and the upgrade card with a full CPU and cache may be more than the circuitry was designed to handle. (You may damage your logic board.)
3. It's unlikely the the adapter board runs at full PPC speed, but if it did then it would either make your upgrade card work at a faster-than-spec speed or cause weird timing problems.
4. G3 upgrades (even new in box) are cheap and readily available for this Mac. They would be several times faster and more stable than this arrangement could ever possibly be.
In short, there is no upside to even trying this.