At one point my distributor on the 2.0 spun itself out. All I had to do was buy another distributor and have someone put the gear on the base (I later learned how to do this) and it was good to go.
When the 2.0 crapped out I simply bought a 2.3 short block and had it installed (had to do the slave so at the time I had someone do it for me).
With this short block (which was Fuel Injected but had the gear for the distributor) I put the distributor from my 2.0 into the 2.3 and it has been running with it ever since (about 60,000 kilometers on it so far in this configuration)...
So...I'd have to say there is something else wrong...not a mismatch, but a problem with the gear or the way the distributor is lining up with it...and considering you have been through 2 different engines...that's why I asked if there was any damage to the rotor or cap...
Other than that...sorry, but I'm out of ideas and truly at a loss to say why you've had this problem...
EDIT: OK...I found this...read post #16...it pertains to high volume oil pumps...did you happen to have them put in a high volume oil pump? Also cast gears are more prone to shredding and if you use brass gears they wear bout but don't necessarily shred teeth...
http://forums.corral.net/forums/5-0-5-8-engine-tech/989666-cam-eating-distributor-gear.html
I simply searched Google for "Ford engine eating distributor gears" and found quite a few hits...haven't read them all but this is a good place to start...and it may or may not pertain to the 2.3...but Ford is, apparently, notorious for having the distributor gear shredded when using a high volume oil pump...or other causes...
EDIT II: Also found this one...the guy figured it out as a ridge inside the engine and when he shimmed the distributor (and other things) he fixed the problem...
http://www.twoguysgarage.com/forum/showthread.php?t=5726
You are not alone Dan!