Which t-56 for 5.7 hemi

Me an my dad have been wanting to restore a demon for a long time so I've been wanting to go ahead and build a 5.7(400-450hp NA) and I'm gonna throw a t-56 behind it while im looking for a good deal on a demon. I see there is a gm, ford, and viper versions but what would have the best gearing. I'm going to get it brand new cause I don't want to finally put a tranny in and find out its blown so a part number would be awesome