Well I have a 55 2nd, and I love it. I do see them around now and then, but seem to see more of the 57 variety.
It's not that I don't like the 57 grill or quad headlights (like red58 sez), I just prefer the 55 grill and single headlight look. I guess it's just a matter of taste.
My dad was an auto mechanic and we worked on many cars and trucks together when I was growing up. Glad to see you have a son that is interested in such things.
Good luck on you project!