that emblem is indeed for a V8 equipped truck - if it was originally a V8 it would also have "V"s on the doors right behind the fender spear, and there would be brackets riveted on the back of the front cross member where the 265/283 front mounting pegs sat, those brackets would not be there on a 235 equipped truck or would be bolted on if the truck had been changed to a V8 - also the V8 truck vins started with a V, as in V3A57xxxxx for your 57 3100
the fact that only the V8 emblem is reproduced means nothing other than that's what sells
Bill
