Something you guys need to start checking out, when you go to smaller diameter convertors, is the clearance between the flexplate tone ring and the actual convertor body itself.
I just got a 9.5" 4500 convertor, and I had it flipped upside down on the bench and was test fitting a 318 Maggy flexplate to it. I noticed that the flexplate was being held about .060" or so above the bolt pads on the convertor. What is hitting is the tone ring on the actual welds of where the face of the convertor is welded to the body. So not something that can be "ground down" to get rid of it. And just ignoring it, and bolting the convertor down, could cause all sorts of issues with keeping convertor bolts tight, and putting extra stress on the flexplate causing it to crack and break easier.
Only real solution ( other than converting to MS and a crank trigger ) is to mill down the flexplate tone ring area.
Also dont forget to make sure that the flexplate to crank bolts are shallow enough on the head that they dont contact the convertor when installed! This can wipe a pump on a trans, or the thrust bearings in the engine! Ive seen it cost guys both a motor and a trans... so be careful on this, and it is a KNOWN Mopar issue.