I need to check into a converter myself. Read some threads on here about the Camaro converter for ZL1. I won't be racing so I don't need a high stall. As far a I can tell they are 1800 rpm. If your looking for a 3.45 diff I have 1 in a auction right now for $300 plus shipping. If interested I could pull some strings for forum fam.
The ZL1 is a good upgrade for a blower car for sure. It would also be a little upgrade for an N/A car. I would give a reputable shop a call and discuss your goals with them. I actually sold the original one I bought for this one, otherwise I would offer to sell it to you.
I would be interested in more information for sure. Miles, etc.