No, actually, no one can tell you that. Reason being, neither a "Blender Unit" nor a "SM64 Unit" are really defined. You need an actual, physical quantity in order to relate measurements.
A real-world estimate
of an SM64 Unit could
be made by taking careful pixel measurements, working under one (and only
one) of the following assumptions: That Mario is the height
of an average human; That Mario is the width
of an average human; That Mario's jump height is equivalent to that of an average human.
In order to use that last one, you also
need to assume that physics work the same way in the Mario universe as in the real one.
Alternatively, you could work under the assumption that Mario walks or runs
at the same speed as an average human, and note that Mario runs at approximately 22 units per frame
, which equals 660 units per second
Note that all these require assumptions,
which may or may not (most likely "not") be accurate.
And all that difficulty is just on the SM64 side of the problem! The Blender side is, fortunately, easier. As I mentioned, a Blender Unit has no world-defined size. You can configure Blender to treat 1 BU as equal 1 meter, or 1 centimeter, or 1 Foot, or 1 Inch, or 1... literally any other unit of distance. Just "A Blender Unit", however, is meaningless.
Now, I do
realize you have been inactive for over half a year, but I hope maybe you'll come back and see this, or else it will prove helpful to someone else. We'll just have to wait and see, I suppose.
A word fitly spoken is like apples of gold in pictures of silver.