I just did some checking on the WINCAPS program and it appears that the 24 valve 3.0's must use the larger T-case from the 3.5's. The countershaft gear part number is the same as what's used on the 3.5 V6's. It's also different from the countershaft gear used on my 3.0 V6. Also, the chain is the same part number as that used on the 3.5's.

Kirk, I hate to say it, but I also think you're screwed.
It looks like the 2.85 gears will only fit the Gen II's through 1994 or those with the 12 valve 3.0's. Let me know if I can track down any part numbers for you.