A904 high performance rebuild--advice wanted

since I have ever started messing with mopars they sayig always was, a 904 is lighter then a 727 but will cost more then a 727 would to build, go with a 727 and have no problems.... that being said I have found that converters are way harder to come by used and a lot more expensive to buy new for a 904. I have changed my build and I am now getting ready to send off my 727 for rebuild and shelf my 904