Ok let's say for arguments sake one could pull the gear without distoring the shaft.
Next you would weld the tapped backplate onto the shaft (hopefully the heat from the weld won't distort the shaft).
Now you machine the stock gear to remove as much of the stock back plate without comprimising integrity. Cut the 3 holes for the bolts and bore out the center of the gear.
Before you pulled the gear, you would of been smart and marked/notched it's location on the shaft, so you put it back on and tighten it at this location.
If you welded the new backing plate at the proper locatin everything should line up.
So as long as you can pull the gear and weld onto the shaft without distorting it, this can work right? If so I'll see when my Brother In Law goes back on midnights (so he can do the machine work for me) and get him to pull this off on my extra set of 2.5L cams - unless of course my thoery has flaws.
2000 Cougar V6 MTX
2001 3.0L Swap w/ PnP Heads - It ran, it boomed, it RUNS AGAIN

Nearly all suspension mods
Big ass stereo
...and more...
See Her Here