Don't take my comments wrong - I'm no purist. I have no problem with modifying these trucks. Make it your own and enjoy it. My comment was directed at bolting old sheetmetal (or fiberglass for that matter) onto a new, completely different frame like what my aquaintance did. The heart of the "old truck" is gone. Its not an "old" truck anymore. It can still be totally cool, but to me it's a newer truck with a facelift. Thats my opinion. I think that the '46 is better looking than a S10 anyway.
So, in the end, do whatever you want. Enjoy it your own way and dont mind those of us with different opinions.
