54 and 55 are essentially the same. 56 is different.
Roadmaster (Series 70) is not the same as Special (Series 40) - different lengths. Absolutely will not work.
I already told you over a year ago that I have a power steering set-up for a 1954 Roadmaster I can sell you, but you never did anything about it, despite several rounds of back and forth communication. You never even asked for a price.