no, by 58 the 6cyl and V8 rad was always riveted in the same location, which is the position that the 6cyl rad was in 55-7 - that's why I'm sure the 58 frame rad location will be correct for putting on your earlier front - go with it for your mods, using reference points on the frame for getting the mounts properly positioned on the clip .... just need to remember the front horns are a couple inches too long for bumper mounting
the factory V8 mounts are the brackets riveted to the front cross member holding the pegs with rubber donuts on, which bolted to the front of the 283 - you won't be using them, but worth salvaging for someone
the other thing you'll want to consider is where the hand brake cross shaft is riveted to the driver side rail (already removed) - might want that later for setting up the original style e-brake
for the link in your sig line, you need to remove that "/url" from the end of the address (change to /albums/) and then add: [/url] after the word Pics ... like so
[ url=http://www.my.opera.com/Oleblue55/albums/]1955 Truck Progress Pics[/url ]
[[remove spaces beginning and end and it'll be "live"]]
Bill