You can't beat a blower for producing power. We've got a 460 with a 671 on top, 10% underdriven and 14 psi of boost.
BUT..plopping a blower kit on your stock 351m is not going to work very well or very long for a number of reasons, not the least of which is the lousy quench characteristics of the stock engine. In simple terms..it cannot stand the increased dynamic compression you will get from the blower.
If you changed to the 400 crank and used forged 32cc zero-deck pistons with Aussie, CHI or Edelbrock closed-chamber heads and a very conservative blower drive (maybe 15% under) you would have a torque monster that might live for a while. The pistons, heads and related machine work are all pretty expensive
We live and breath extreme 400 (we refer to them as 'Super Clevelands') builds here at our shop..but for the cost and results, I would have to say the 460 would be a better foundation for a supercharged engine.