. i have done 4 or 5 different styles of suspensions on 55s .
i have done 605 on a stock frame , it drives ok
also have done rack on a stock frame , again better than 605
a full tube chassis on a 55 with no power rack , a little to heavy for no ps
i have done a mustang 2 clip on a nomad best yet .
the best i think is a clip change , not a camaro or nova(( they look like crap ) . like a scotts hot rod clip that is designed for a 55 -57 .
if you can afford a full afertmarket frame like you mentioned .
i have seen all 3 you mentioned under cars they all look good ,
the roadster shop was a real nice part under a 56 nomad .
and morrison was showing the 55 all last year it aslo looked real good .