An M-116 iron block is a 3.5 liter. It's a sweet running engine - I had one in my long gone grey market 350SLC. Not as much torque as the U.S. spec 4.5s, but actually more HP, although at higher revs - and that motor just purrs once it comes up on the cam at around 4000 RPMs.
Ditto everything that M.B.Doc said except that the 4.5 injection components are blue, not green. (Unless I am colorblind, or unless they have changed the color codes. You never know....)