first,NOTHING looks meaner than a 413-426 super stock w/ cross ram and maxie exhaust,but,go with a th400 or a 4-5 speed manual,that will handle the tq. the allison shifts to stupid to be fun like a 400 or a 4spd.consider a hemi 833 4spd.there the strongest,and well,its a mopar,YAH!coversion...