As a pre '64 model 70 owner myself, I like the suggestion of not messing with the original stock, but instead buying a new stock and bedding the rifle into the new one. My own model 70 is plenty accurate enough, so I'm lucky I guess that I haven't had to do anything to it. I would not want to alter the original stock, but that's just me.
Take a look at this site for a possible replacement stock:
www.boydboys.com