I saw a pretty violent transmission explosion on the dyno when an N/A high STR converter was installed in a nitrous car. The torque multiplication was high enough to scatter some really expensive internals when the second stage came on. Call a real converter builder for a recommendation. Neal Chance, Pro Torque, PTC, come to mind. If its an off the shelf unit from a wholesaler, you can be sure it won't be optimal to your combo.