I had one too in my original 57' fuelie back in the day but you are mistaken on the bore required to get a 301..it takes a 4" bore and that is .125 where I went to school. I know of several 283's that had walls too thin to punch out that far and would run very hot. Best be careful if it's a 57' block. Later model's had thicker walls I've heard. Mine had 12.5/1 Jahns and would only run on Sunoco 260 w/o retarding the timing and then it ran terrible.
